1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * NETLINK Kernel-user communication protocol.
5 * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
6 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
7 * Patrick McHardy <kaber@trash.net>
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
21 #include <linux/module.h>
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>
35 #include <linux/fcntl.h>
36 #include <linux/termios.h>
37 #include <linux/sockios.h>
38 #include <linux/net.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>
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>
67 #include <net/net_namespace.h>
68 #include <net/netns/generic.h>
71 #include <net/netlink.h>
72 #define CREATE_TRACE_POINTS
73 #include <trace/events/netlink.h>
75 #include "af_netlink.h"
79 unsigned long masks
[];
83 #define NETLINK_S_CONGESTED 0x0
85 static inline int netlink_is_kernel(struct sock
*sk
)
87 return nlk_test_bit(KERNEL_SOCKET
, sk
);
90 struct netlink_table
*nl_table __read_mostly
;
91 EXPORT_SYMBOL_GPL(nl_table
);
93 static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait
);
95 static struct lock_class_key nlk_cb_mutex_keys
[MAX_LINKS
];
97 static const char *const nlk_cb_mutex_key_strings
[MAX_LINKS
+ 1] = {
100 "nlk_cb_mutex-USERSOCK",
101 "nlk_cb_mutex-FIREWALL",
102 "nlk_cb_mutex-SOCK_DIAG",
103 "nlk_cb_mutex-NFLOG",
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",
116 "nlk_cb_mutex-SCSITRANSPORT",
117 "nlk_cb_mutex-ECRYPTFS",
119 "nlk_cb_mutex-CRYPTO",
130 "nlk_cb_mutex-MAX_LINKS"
133 static int netlink_dump(struct sock
*sk
);
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.
143 DEFINE_RWLOCK(nl_table_lock
);
144 EXPORT_SYMBOL_GPL(nl_table_lock
);
145 static atomic_t nl_table_users
= ATOMIC_INIT(0);
147 #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
149 static BLOCKING_NOTIFIER_HEAD(netlink_chain
);
152 static const struct rhashtable_params netlink_rhashtable_params
;
154 void do_trace_netlink_extack(const char *msg
)
156 trace_netlink_extack(msg
);
158 EXPORT_SYMBOL(do_trace_netlink_extack
);
160 static inline u32
netlink_group_mask(u32 group
)
164 return group
? 1 << (group
- 1) : 0;
167 static struct sk_buff
*netlink_to_full_skb(const struct sk_buff
*skb
,
170 unsigned int len
= skb_end_offset(skb
);
173 new = alloc_skb(len
, gfp_mask
);
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
;
181 skb_put_data(new, skb
->data
, len
);
185 static unsigned int netlink_tap_net_id
;
187 struct netlink_tap_net
{
188 struct list_head netlink_tap_all
;
189 struct mutex netlink_tap_lock
;
192 int netlink_add_tap(struct netlink_tap
*nt
)
194 struct net
*net
= dev_net(nt
->dev
);
195 struct netlink_tap_net
*nn
= net_generic(net
, netlink_tap_net_id
);
197 if (unlikely(nt
->dev
->type
!= ARPHRD_NETLINK
))
200 mutex_lock(&nn
->netlink_tap_lock
);
201 list_add_rcu(&nt
->list
, &nn
->netlink_tap_all
);
202 mutex_unlock(&nn
->netlink_tap_lock
);
204 __module_get(nt
->module
);
208 EXPORT_SYMBOL_GPL(netlink_add_tap
);
210 static int __netlink_remove_tap(struct netlink_tap
*nt
)
212 struct net
*net
= dev_net(nt
->dev
);
213 struct netlink_tap_net
*nn
= net_generic(net
, netlink_tap_net_id
);
215 struct netlink_tap
*tmp
;
217 mutex_lock(&nn
->netlink_tap_lock
);
219 list_for_each_entry(tmp
, &nn
->netlink_tap_all
, list
) {
221 list_del_rcu(&nt
->list
);
227 pr_warn("__netlink_remove_tap: %p not found\n", nt
);
229 mutex_unlock(&nn
->netlink_tap_lock
);
232 module_put(nt
->module
);
234 return found
? 0 : -ENODEV
;
237 int netlink_remove_tap(struct netlink_tap
*nt
)
241 ret
= __netlink_remove_tap(nt
);
246 EXPORT_SYMBOL_GPL(netlink_remove_tap
);
248 static __net_init
int netlink_tap_init_net(struct net
*net
)
250 struct netlink_tap_net
*nn
= net_generic(net
, netlink_tap_net_id
);
252 INIT_LIST_HEAD(&nn
->netlink_tap_all
);
253 mutex_init(&nn
->netlink_tap_lock
);
257 static struct pernet_operations netlink_tap_net_ops
= {
258 .init
= netlink_tap_init_net
,
259 .id
= &netlink_tap_net_id
,
260 .size
= sizeof(struct netlink_tap_net
),
263 static bool netlink_filter_tap(const struct sk_buff
*skb
)
265 struct sock
*sk
= skb
->sk
;
267 /* We take the more conservative approach and
268 * whitelist socket protocols that may pass.
270 switch (sk
->sk_protocol
) {
272 case NETLINK_USERSOCK
:
273 case NETLINK_SOCK_DIAG
:
276 case NETLINK_FIB_LOOKUP
:
277 case NETLINK_NETFILTER
:
278 case NETLINK_GENERIC
:
285 static int __netlink_deliver_tap_skb(struct sk_buff
*skb
,
286 struct net_device
*dev
)
288 struct sk_buff
*nskb
;
289 struct sock
*sk
= skb
->sk
;
292 if (!net_eq(dev_net(dev
), sock_net(sk
)))
297 if (is_vmalloc_addr(skb
->head
))
298 nskb
= netlink_to_full_skb(skb
, GFP_ATOMIC
);
300 nskb
= skb_clone(skb
, GFP_ATOMIC
);
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
);
316 static void __netlink_deliver_tap(struct sk_buff
*skb
, struct netlink_tap_net
*nn
)
319 struct netlink_tap
*tmp
;
321 if (!netlink_filter_tap(skb
))
324 list_for_each_entry_rcu(tmp
, &nn
->netlink_tap_all
, list
) {
325 ret
= __netlink_deliver_tap_skb(skb
, tmp
->dev
);
331 static void netlink_deliver_tap(struct net
*net
, struct sk_buff
*skb
)
333 struct netlink_tap_net
*nn
= net_generic(net
, netlink_tap_net_id
);
337 if (unlikely(!list_empty(&nn
->netlink_tap_all
)))
338 __netlink_deliver_tap(skb
, nn
);
343 static void netlink_deliver_tap_kernel(struct sock
*dst
, struct sock
*src
,
346 if (!(netlink_is_kernel(dst
) && netlink_is_kernel(src
)))
347 netlink_deliver_tap(sock_net(dst
), skb
);
350 static void netlink_overrun(struct sock
*sk
)
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
);
359 atomic_inc(&sk
->sk_drops
);
362 static void netlink_rcv_wake(struct sock
*sk
)
364 struct netlink_sock
*nlk
= nlk_sk(sk
);
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
);
372 static void netlink_skb_destructor(struct sk_buff
*skb
)
374 if (is_vmalloc_addr(skb
->head
)) {
376 !atomic_dec_return(&(skb_shinfo(skb
)->dataref
)))
385 static void netlink_skb_set_owner_r(struct sk_buff
*skb
, struct sock
*sk
)
387 WARN_ON(skb
->sk
!= NULL
);
389 skb
->destructor
= netlink_skb_destructor
;
390 atomic_add(skb
->truesize
, &sk
->sk_rmem_alloc
);
391 sk_mem_charge(sk
, skb
->truesize
);
394 static void netlink_sock_destruct(struct sock
*sk
)
396 struct netlink_sock
*nlk
= nlk_sk(sk
);
398 if (nlk
->cb_running
) {
400 nlk
->cb
.done(&nlk
->cb
);
401 module_put(nlk
->cb
.module
);
402 kfree_skb(nlk
->cb
.skb
);
405 skb_queue_purge(&sk
->sk_receive_queue
);
407 if (!sock_flag(sk
, SOCK_DEAD
)) {
408 printk(KERN_ERR
"Freeing alive netlink socket %p\n", sk
);
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
);
417 static void netlink_sock_destruct_work(struct work_struct
*work
)
419 struct netlink_sock
*nlk
= container_of(work
, struct netlink_sock
,
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.
431 void netlink_table_grab(void)
432 __acquires(nl_table_lock
)
436 write_lock_irq(&nl_table_lock
);
438 if (atomic_read(&nl_table_users
)) {
439 DECLARE_WAITQUEUE(wait
, current
);
441 add_wait_queue_exclusive(&nl_table_wait
, &wait
);
443 set_current_state(TASK_UNINTERRUPTIBLE
);
444 if (atomic_read(&nl_table_users
) == 0)
446 write_unlock_irq(&nl_table_lock
);
448 write_lock_irq(&nl_table_lock
);
451 __set_current_state(TASK_RUNNING
);
452 remove_wait_queue(&nl_table_wait
, &wait
);
456 void netlink_table_ungrab(void)
457 __releases(nl_table_lock
)
459 write_unlock_irq(&nl_table_lock
);
460 wake_up(&nl_table_wait
);
464 netlink_lock_table(void)
468 /* read_lock() synchronizes us to netlink_table_grab */
470 read_lock_irqsave(&nl_table_lock
, flags
);
471 atomic_inc(&nl_table_users
);
472 read_unlock_irqrestore(&nl_table_lock
, flags
);
476 netlink_unlock_table(void)
478 if (atomic_dec_and_test(&nl_table_users
))
479 wake_up(&nl_table_wait
);
482 struct netlink_compare_arg
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))
492 static inline int netlink_compare(struct rhashtable_compare_arg
*arg
,
495 const struct netlink_compare_arg
*x
= arg
->key
;
496 const struct netlink_sock
*nlk
= ptr
;
498 return nlk
->portid
!= x
->portid
||
499 !net_eq(sock_net(&nlk
->sk
), read_pnet(&x
->pnet
));
502 static void netlink_compare_arg_init(struct netlink_compare_arg
*arg
,
503 struct net
*net
, u32 portid
)
505 memset(arg
, 0, sizeof(*arg
));
506 write_pnet(&arg
->pnet
, net
);
507 arg
->portid
= portid
;
510 static struct sock
*__netlink_lookup(struct netlink_table
*table
, u32 portid
,
513 struct netlink_compare_arg arg
;
515 netlink_compare_arg_init(&arg
, net
, portid
);
516 return rhashtable_lookup_fast(&table
->hash
, &arg
,
517 netlink_rhashtable_params
);
520 static int __netlink_insert(struct netlink_table
*table
, struct sock
*sk
)
522 struct netlink_compare_arg arg
;
524 netlink_compare_arg_init(&arg
, sock_net(sk
), nlk_sk(sk
)->portid
);
525 return rhashtable_lookup_insert_key(&table
->hash
, &arg
,
527 netlink_rhashtable_params
);
530 static struct sock
*netlink_lookup(struct net
*net
, int protocol
, u32 portid
)
532 struct netlink_table
*table
= &nl_table
[protocol
];
536 sk
= __netlink_lookup(table
, portid
, net
);
544 static const struct proto_ops netlink_ops
;
547 netlink_update_listeners(struct sock
*sk
)
549 struct netlink_table
*tbl
= &nl_table
[sk
->sk_protocol
];
552 struct listeners
*listeners
;
554 listeners
= nl_deref_protected(tbl
->listeners
);
558 for (i
= 0; i
< NLGRPLONGS(tbl
->groups
); i
++) {
560 sk_for_each_bound(sk
, &tbl
->mc_list
) {
561 if (i
< NLGRPLONGS(nlk_sk(sk
)->ngroups
))
562 mask
|= nlk_sk(sk
)->groups
[i
];
564 listeners
->masks
[i
] = mask
;
566 /* this function is only called with the netlink table "grabbed", which
567 * makes sure updates are visible before bind or setsockopt return. */
570 static int netlink_insert(struct sock
*sk
, u32 portid
)
572 struct netlink_table
*table
= &nl_table
[sk
->sk_protocol
];
577 err
= nlk_sk(sk
)->portid
== portid
? 0 : -EBUSY
;
578 if (nlk_sk(sk
)->bound
)
581 /* portid can be read locklessly from netlink_getname(). */
582 WRITE_ONCE(nlk_sk(sk
)->portid
, portid
);
586 err
= __netlink_insert(table
, sk
);
588 /* In case the hashtable backend returns with -EBUSY
589 * from here, it must not escape to the caller.
591 if (unlikely(err
== -EBUSY
))
599 /* We need to ensure that the socket is hashed and visible. */
601 /* Paired with lockless reads from netlink_bind(),
602 * netlink_connect() and netlink_sendmsg().
604 WRITE_ONCE(nlk_sk(sk
)->bound
, portid
);
611 static void netlink_remove(struct sock
*sk
)
613 struct netlink_table
*table
;
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);
622 netlink_table_grab();
623 if (nlk_sk(sk
)->subscriptions
) {
624 __sk_del_bind_node(sk
);
625 netlink_update_listeners(sk
);
627 if (sk
->sk_protocol
== NETLINK_GENERIC
)
628 atomic_inc(&genl_sk_destructing_cnt
);
629 netlink_table_ungrab();
632 static struct proto netlink_proto
= {
634 .owner
= THIS_MODULE
,
635 .obj_size
= sizeof(struct netlink_sock
),
638 static int __netlink_create(struct net
*net
, struct socket
*sock
,
639 struct mutex
*cb_mutex
, int protocol
,
643 struct netlink_sock
*nlk
;
645 sock
->ops
= &netlink_ops
;
647 sk
= sk_alloc(net
, PF_NETLINK
, GFP_KERNEL
, &netlink_proto
, kern
);
651 sock_init_data(sock
, sk
);
655 nlk
->cb_mutex
= cb_mutex
;
657 nlk
->cb_mutex
= &nlk
->cb_def_mutex
;
658 mutex_init(nlk
->cb_mutex
);
659 lockdep_set_class_and_name(nlk
->cb_mutex
,
660 nlk_cb_mutex_keys
+ protocol
,
661 nlk_cb_mutex_key_strings
[protocol
]);
663 init_waitqueue_head(&nlk
->wait
);
665 sk
->sk_destruct
= netlink_sock_destruct
;
666 sk
->sk_protocol
= protocol
;
670 static int netlink_create(struct net
*net
, struct socket
*sock
, int protocol
,
673 struct module
*module
= NULL
;
674 struct mutex
*cb_mutex
;
675 struct netlink_sock
*nlk
;
676 int (*bind
)(struct net
*net
, int group
);
677 void (*unbind
)(struct net
*net
, int group
);
678 void (*release
)(struct sock
*sock
, unsigned long *groups
);
681 sock
->state
= SS_UNCONNECTED
;
683 if (sock
->type
!= SOCK_RAW
&& sock
->type
!= SOCK_DGRAM
)
684 return -ESOCKTNOSUPPORT
;
686 if (protocol
< 0 || protocol
>= MAX_LINKS
)
687 return -EPROTONOSUPPORT
;
688 protocol
= array_index_nospec(protocol
, MAX_LINKS
);
690 netlink_lock_table();
691 #ifdef CONFIG_MODULES
692 if (!nl_table
[protocol
].registered
) {
693 netlink_unlock_table();
694 request_module("net-pf-%d-proto-%d", PF_NETLINK
, protocol
);
695 netlink_lock_table();
698 if (nl_table
[protocol
].registered
&&
699 try_module_get(nl_table
[protocol
].module
))
700 module
= nl_table
[protocol
].module
;
702 err
= -EPROTONOSUPPORT
;
703 cb_mutex
= nl_table
[protocol
].cb_mutex
;
704 bind
= nl_table
[protocol
].bind
;
705 unbind
= nl_table
[protocol
].unbind
;
706 release
= nl_table
[protocol
].release
;
707 netlink_unlock_table();
712 err
= __netlink_create(net
, sock
, cb_mutex
, protocol
, kern
);
716 sock_prot_inuse_add(net
, &netlink_proto
, 1);
718 nlk
= nlk_sk(sock
->sk
);
719 nlk
->module
= module
;
720 nlk
->netlink_bind
= bind
;
721 nlk
->netlink_unbind
= unbind
;
722 nlk
->netlink_release
= release
;
731 static void deferred_put_nlk_sk(struct rcu_head
*head
)
733 struct netlink_sock
*nlk
= container_of(head
, struct netlink_sock
, rcu
);
734 struct sock
*sk
= &nlk
->sk
;
739 if (!refcount_dec_and_test(&sk
->sk_refcnt
))
742 if (nlk
->cb_running
&& nlk
->cb
.done
) {
743 INIT_WORK(&nlk
->work
, netlink_sock_destruct_work
);
744 schedule_work(&nlk
->work
);
751 static int netlink_release(struct socket
*sock
)
753 struct sock
*sk
= sock
->sk
;
754 struct netlink_sock
*nlk
;
764 * OK. Socket is unlinked, any packets that arrive now
767 if (nlk
->netlink_release
)
768 nlk
->netlink_release(sk
, nlk
->groups
);
770 /* must not acquire netlink_table_lock in any way again before unbind
771 * and notifying genetlink is done as otherwise it might deadlock
773 if (nlk
->netlink_unbind
) {
776 for (i
= 0; i
< nlk
->ngroups
; i
++)
777 if (test_bit(i
, nlk
->groups
))
778 nlk
->netlink_unbind(sock_net(sk
), i
+ 1);
780 if (sk
->sk_protocol
== NETLINK_GENERIC
&&
781 atomic_dec_return(&genl_sk_destructing_cnt
) == 0)
782 wake_up(&genl_sk_destructing_waitq
);
785 wake_up_interruptible_all(&nlk
->wait
);
787 skb_queue_purge(&sk
->sk_write_queue
);
789 if (nlk
->portid
&& nlk
->bound
) {
790 struct netlink_notify n
= {
792 .protocol
= sk
->sk_protocol
,
793 .portid
= nlk
->portid
,
795 blocking_notifier_call_chain(&netlink_chain
,
796 NETLINK_URELEASE
, &n
);
799 module_put(nlk
->module
);
801 if (netlink_is_kernel(sk
)) {
802 netlink_table_grab();
803 BUG_ON(nl_table
[sk
->sk_protocol
].registered
== 0);
804 if (--nl_table
[sk
->sk_protocol
].registered
== 0) {
805 struct listeners
*old
;
807 old
= nl_deref_protected(nl_table
[sk
->sk_protocol
].listeners
);
808 RCU_INIT_POINTER(nl_table
[sk
->sk_protocol
].listeners
, NULL
);
810 nl_table
[sk
->sk_protocol
].module
= NULL
;
811 nl_table
[sk
->sk_protocol
].bind
= NULL
;
812 nl_table
[sk
->sk_protocol
].unbind
= NULL
;
813 nl_table
[sk
->sk_protocol
].flags
= 0;
814 nl_table
[sk
->sk_protocol
].registered
= 0;
816 netlink_table_ungrab();
819 sock_prot_inuse_add(sock_net(sk
), &netlink_proto
, -1);
821 /* Because struct net might disappear soon, do not keep a pointer. */
822 if (!sk
->sk_net_refcnt
&& sock_net(sk
) != &init_net
) {
823 __netns_tracker_free(sock_net(sk
), &sk
->ns_tracker
, false);
824 /* Because of deferred_put_nlk_sk and use of work queue,
825 * it is possible netns will be freed before this socket.
827 sock_net_set(sk
, &init_net
);
828 __netns_tracker_alloc(&init_net
, &sk
->ns_tracker
,
831 call_rcu(&nlk
->rcu
, deferred_put_nlk_sk
);
835 static int netlink_autobind(struct socket
*sock
)
837 struct sock
*sk
= sock
->sk
;
838 struct net
*net
= sock_net(sk
);
839 struct netlink_table
*table
= &nl_table
[sk
->sk_protocol
];
840 s32 portid
= task_tgid_vnr(current
);
848 ok
= !__netlink_lookup(table
, portid
, net
);
851 /* Bind collision, search negative portid values. */
853 /* rover will be in range [S32_MIN, -4097] */
854 rover
= S32_MIN
+ get_random_u32_below(-4096 - S32_MIN
);
855 else if (rover
>= -4096)
861 err
= netlink_insert(sk
, portid
);
862 if (err
== -EADDRINUSE
)
865 /* If 2 threads race to autobind, that is fine. */
873 * __netlink_ns_capable - General netlink message capability test
874 * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
875 * @user_ns: The user namespace of the capability to use
876 * @cap: The capability to use
878 * Test to see if the opener of the socket we received the message
879 * from had when the netlink socket was created and the sender of the
880 * message has the capability @cap in the user namespace @user_ns.
882 bool __netlink_ns_capable(const struct netlink_skb_parms
*nsp
,
883 struct user_namespace
*user_ns
, int cap
)
885 return ((nsp
->flags
& NETLINK_SKB_DST
) ||
886 file_ns_capable(nsp
->sk
->sk_socket
->file
, user_ns
, cap
)) &&
887 ns_capable(user_ns
, cap
);
889 EXPORT_SYMBOL(__netlink_ns_capable
);
892 * netlink_ns_capable - General netlink message capability test
893 * @skb: socket buffer holding a netlink command from userspace
894 * @user_ns: The user namespace of the capability to use
895 * @cap: The capability to use
897 * Test to see if the opener of the socket we received the message
898 * from had when the netlink socket was created and the sender of the
899 * message has the capability @cap in the user namespace @user_ns.
901 bool netlink_ns_capable(const struct sk_buff
*skb
,
902 struct user_namespace
*user_ns
, int cap
)
904 return __netlink_ns_capable(&NETLINK_CB(skb
), user_ns
, cap
);
906 EXPORT_SYMBOL(netlink_ns_capable
);
909 * netlink_capable - Netlink global message capability test
910 * @skb: socket buffer holding a netlink command from userspace
911 * @cap: The capability to use
913 * Test to see if the opener of the socket we received the message
914 * from had when the netlink socket was created and the sender of the
915 * message has the capability @cap in all user namespaces.
917 bool netlink_capable(const struct sk_buff
*skb
, int cap
)
919 return netlink_ns_capable(skb
, &init_user_ns
, cap
);
921 EXPORT_SYMBOL(netlink_capable
);
924 * netlink_net_capable - Netlink network namespace message capability test
925 * @skb: socket buffer holding a netlink command from userspace
926 * @cap: The capability to use
928 * Test to see if the opener of the socket we received the message
929 * from had when the netlink socket was created and the sender of the
930 * message has the capability @cap over the network namespace of
931 * the socket we received the message from.
933 bool netlink_net_capable(const struct sk_buff
*skb
, int cap
)
935 return netlink_ns_capable(skb
, sock_net(skb
->sk
)->user_ns
, cap
);
937 EXPORT_SYMBOL(netlink_net_capable
);
939 static inline int netlink_allowed(const struct socket
*sock
, unsigned int flag
)
941 return (nl_table
[sock
->sk
->sk_protocol
].flags
& flag
) ||
942 ns_capable(sock_net(sock
->sk
)->user_ns
, CAP_NET_ADMIN
);
946 netlink_update_subscriptions(struct sock
*sk
, unsigned int subscriptions
)
948 struct netlink_sock
*nlk
= nlk_sk(sk
);
950 if (nlk
->subscriptions
&& !subscriptions
)
951 __sk_del_bind_node(sk
);
952 else if (!nlk
->subscriptions
&& subscriptions
)
953 sk_add_bind_node(sk
, &nl_table
[sk
->sk_protocol
].mc_list
);
954 nlk
->subscriptions
= subscriptions
;
957 static int netlink_realloc_groups(struct sock
*sk
)
959 struct netlink_sock
*nlk
= nlk_sk(sk
);
961 unsigned long *new_groups
;
964 netlink_table_grab();
966 groups
= nl_table
[sk
->sk_protocol
].groups
;
967 if (!nl_table
[sk
->sk_protocol
].registered
) {
972 if (nlk
->ngroups
>= groups
)
975 new_groups
= krealloc(nlk
->groups
, NLGRPSZ(groups
), GFP_ATOMIC
);
976 if (new_groups
== NULL
) {
980 memset((char *)new_groups
+ NLGRPSZ(nlk
->ngroups
), 0,
981 NLGRPSZ(groups
) - NLGRPSZ(nlk
->ngroups
));
983 nlk
->groups
= new_groups
;
984 nlk
->ngroups
= groups
;
986 netlink_table_ungrab();
990 static void netlink_undo_bind(int group
, long unsigned int groups
,
993 struct netlink_sock
*nlk
= nlk_sk(sk
);
996 if (!nlk
->netlink_unbind
)
999 for (undo
= 0; undo
< group
; undo
++)
1000 if (test_bit(undo
, &groups
))
1001 nlk
->netlink_unbind(sock_net(sk
), undo
+ 1);
1004 static int netlink_bind(struct socket
*sock
, struct sockaddr
*addr
,
1007 struct sock
*sk
= sock
->sk
;
1008 struct net
*net
= sock_net(sk
);
1009 struct netlink_sock
*nlk
= nlk_sk(sk
);
1010 struct sockaddr_nl
*nladdr
= (struct sockaddr_nl
*)addr
;
1012 unsigned long groups
;
1015 if (addr_len
< sizeof(struct sockaddr_nl
))
1018 if (nladdr
->nl_family
!= AF_NETLINK
)
1020 groups
= nladdr
->nl_groups
;
1022 /* Only superuser is allowed to listen multicasts */
1024 if (!netlink_allowed(sock
, NL_CFG_F_NONROOT_RECV
))
1026 err
= netlink_realloc_groups(sk
);
1031 if (nlk
->ngroups
< BITS_PER_LONG
)
1032 groups
&= (1UL << nlk
->ngroups
) - 1;
1034 /* Paired with WRITE_ONCE() in netlink_insert() */
1035 bound
= READ_ONCE(nlk
->bound
);
1037 /* Ensure nlk->portid is up-to-date. */
1040 if (nladdr
->nl_pid
!= nlk
->portid
)
1044 if (nlk
->netlink_bind
&& groups
) {
1047 /* nl_groups is a u32, so cap the maximum groups we can bind */
1048 for (group
= 0; group
< BITS_PER_TYPE(u32
); group
++) {
1049 if (!test_bit(group
, &groups
))
1051 err
= nlk
->netlink_bind(net
, group
+ 1);
1054 netlink_undo_bind(group
, groups
, sk
);
1059 /* No need for barriers here as we return to user-space without
1060 * using any of the bound attributes.
1062 netlink_lock_table();
1064 err
= nladdr
->nl_pid
?
1065 netlink_insert(sk
, nladdr
->nl_pid
) :
1066 netlink_autobind(sock
);
1068 netlink_undo_bind(BITS_PER_TYPE(u32
), groups
, sk
);
1073 if (!groups
&& (nlk
->groups
== NULL
|| !(u32
)nlk
->groups
[0]))
1075 netlink_unlock_table();
1077 netlink_table_grab();
1078 netlink_update_subscriptions(sk
, nlk
->subscriptions
+
1080 hweight32(nlk
->groups
[0]));
1081 nlk
->groups
[0] = (nlk
->groups
[0] & ~0xffffffffUL
) | groups
;
1082 netlink_update_listeners(sk
);
1083 netlink_table_ungrab();
1088 netlink_unlock_table();
1092 static int netlink_connect(struct socket
*sock
, struct sockaddr
*addr
,
1093 int alen
, int flags
)
1096 struct sock
*sk
= sock
->sk
;
1097 struct netlink_sock
*nlk
= nlk_sk(sk
);
1098 struct sockaddr_nl
*nladdr
= (struct sockaddr_nl
*)addr
;
1100 if (alen
< sizeof(addr
->sa_family
))
1103 if (addr
->sa_family
== AF_UNSPEC
) {
1104 /* paired with READ_ONCE() in netlink_getsockbyportid() */
1105 WRITE_ONCE(sk
->sk_state
, NETLINK_UNCONNECTED
);
1106 /* dst_portid and dst_group can be read locklessly */
1107 WRITE_ONCE(nlk
->dst_portid
, 0);
1108 WRITE_ONCE(nlk
->dst_group
, 0);
1111 if (addr
->sa_family
!= AF_NETLINK
)
1114 if (alen
< sizeof(struct sockaddr_nl
))
1117 if ((nladdr
->nl_groups
|| nladdr
->nl_pid
) &&
1118 !netlink_allowed(sock
, NL_CFG_F_NONROOT_SEND
))
1121 /* No need for barriers here as we return to user-space without
1122 * using any of the bound attributes.
1123 * Paired with WRITE_ONCE() in netlink_insert().
1125 if (!READ_ONCE(nlk
->bound
))
1126 err
= netlink_autobind(sock
);
1129 /* paired with READ_ONCE() in netlink_getsockbyportid() */
1130 WRITE_ONCE(sk
->sk_state
, NETLINK_CONNECTED
);
1131 /* dst_portid and dst_group can be read locklessly */
1132 WRITE_ONCE(nlk
->dst_portid
, nladdr
->nl_pid
);
1133 WRITE_ONCE(nlk
->dst_group
, ffs(nladdr
->nl_groups
));
1139 static int netlink_getname(struct socket
*sock
, struct sockaddr
*addr
,
1142 struct sock
*sk
= sock
->sk
;
1143 struct netlink_sock
*nlk
= nlk_sk(sk
);
1144 DECLARE_SOCKADDR(struct sockaddr_nl
*, nladdr
, addr
);
1146 nladdr
->nl_family
= AF_NETLINK
;
1150 /* Paired with WRITE_ONCE() in netlink_connect() */
1151 nladdr
->nl_pid
= READ_ONCE(nlk
->dst_portid
);
1152 nladdr
->nl_groups
= netlink_group_mask(READ_ONCE(nlk
->dst_group
));
1154 /* Paired with WRITE_ONCE() in netlink_insert() */
1155 nladdr
->nl_pid
= READ_ONCE(nlk
->portid
);
1156 netlink_lock_table();
1157 nladdr
->nl_groups
= nlk
->groups
? nlk
->groups
[0] : 0;
1158 netlink_unlock_table();
1160 return sizeof(*nladdr
);
1163 static int netlink_ioctl(struct socket
*sock
, unsigned int cmd
,
1166 /* try to hand this ioctl down to the NIC drivers.
1168 return -ENOIOCTLCMD
;
1171 static struct sock
*netlink_getsockbyportid(struct sock
*ssk
, u32 portid
)
1174 struct netlink_sock
*nlk
;
1176 sock
= netlink_lookup(sock_net(ssk
), ssk
->sk_protocol
, portid
);
1178 return ERR_PTR(-ECONNREFUSED
);
1180 /* Don't bother queuing skb if kernel socket has no input function */
1182 /* dst_portid and sk_state can be changed in netlink_connect() */
1183 if (READ_ONCE(sock
->sk_state
) == NETLINK_CONNECTED
&&
1184 READ_ONCE(nlk
->dst_portid
) != nlk_sk(ssk
)->portid
) {
1186 return ERR_PTR(-ECONNREFUSED
);
1191 struct sock
*netlink_getsockbyfilp(struct file
*filp
)
1193 struct inode
*inode
= file_inode(filp
);
1196 if (!S_ISSOCK(inode
->i_mode
))
1197 return ERR_PTR(-ENOTSOCK
);
1199 sock
= SOCKET_I(inode
)->sk
;
1200 if (sock
->sk_family
!= AF_NETLINK
)
1201 return ERR_PTR(-EINVAL
);
1207 static struct sk_buff
*netlink_alloc_large_skb(unsigned int size
,
1210 struct sk_buff
*skb
;
1213 if (size
<= NLMSG_GOODSIZE
|| broadcast
)
1214 return alloc_skb(size
, GFP_KERNEL
);
1216 size
= SKB_DATA_ALIGN(size
) +
1217 SKB_DATA_ALIGN(sizeof(struct skb_shared_info
));
1219 data
= vmalloc(size
);
1223 skb
= __build_skb(data
, size
);
1227 skb
->destructor
= netlink_skb_destructor
;
1233 * Attach a skb to a netlink socket.
1234 * The caller must hold a reference to the destination socket. On error, the
1235 * reference is dropped. The skb is not send to the destination, just all
1236 * all error checks are performed and memory in the queue is reserved.
1238 * < 0: error. skb freed, reference to sock dropped.
1240 * 1: repeat lookup - reference dropped while waiting for socket memory.
1242 int netlink_attachskb(struct sock
*sk
, struct sk_buff
*skb
,
1243 long *timeo
, struct sock
*ssk
)
1245 struct netlink_sock
*nlk
;
1249 if ((atomic_read(&sk
->sk_rmem_alloc
) > sk
->sk_rcvbuf
||
1250 test_bit(NETLINK_S_CONGESTED
, &nlk
->state
))) {
1251 DECLARE_WAITQUEUE(wait
, current
);
1253 if (!ssk
|| netlink_is_kernel(ssk
))
1254 netlink_overrun(sk
);
1260 __set_current_state(TASK_INTERRUPTIBLE
);
1261 add_wait_queue(&nlk
->wait
, &wait
);
1263 if ((atomic_read(&sk
->sk_rmem_alloc
) > sk
->sk_rcvbuf
||
1264 test_bit(NETLINK_S_CONGESTED
, &nlk
->state
)) &&
1265 !sock_flag(sk
, SOCK_DEAD
))
1266 *timeo
= schedule_timeout(*timeo
);
1268 __set_current_state(TASK_RUNNING
);
1269 remove_wait_queue(&nlk
->wait
, &wait
);
1272 if (signal_pending(current
)) {
1274 return sock_intr_errno(*timeo
);
1278 netlink_skb_set_owner_r(skb
, sk
);
1282 static int __netlink_sendskb(struct sock
*sk
, struct sk_buff
*skb
)
1286 netlink_deliver_tap(sock_net(sk
), skb
);
1288 skb_queue_tail(&sk
->sk_receive_queue
, skb
);
1289 sk
->sk_data_ready(sk
);
1293 int netlink_sendskb(struct sock
*sk
, struct sk_buff
*skb
)
1295 int len
= __netlink_sendskb(sk
, skb
);
1301 void netlink_detachskb(struct sock
*sk
, struct sk_buff
*skb
)
1307 static struct sk_buff
*netlink_trim(struct sk_buff
*skb
, gfp_t allocation
)
1311 WARN_ON(skb
->sk
!= NULL
);
1312 delta
= skb
->end
- skb
->tail
;
1313 if (is_vmalloc_addr(skb
->head
) || delta
* 2 < skb
->truesize
)
1316 if (skb_shared(skb
)) {
1317 struct sk_buff
*nskb
= skb_clone(skb
, allocation
);
1324 pskb_expand_head(skb
, 0, -delta
,
1325 (allocation
& ~__GFP_DIRECT_RECLAIM
) |
1326 __GFP_NOWARN
| __GFP_NORETRY
);
1330 static int netlink_unicast_kernel(struct sock
*sk
, struct sk_buff
*skb
,
1334 struct netlink_sock
*nlk
= nlk_sk(sk
);
1336 ret
= -ECONNREFUSED
;
1337 if (nlk
->netlink_rcv
!= NULL
) {
1339 netlink_skb_set_owner_r(skb
, sk
);
1340 NETLINK_CB(skb
).sk
= ssk
;
1341 netlink_deliver_tap_kernel(sk
, ssk
, skb
);
1342 nlk
->netlink_rcv(skb
);
1351 int netlink_unicast(struct sock
*ssk
, struct sk_buff
*skb
,
1352 u32 portid
, int nonblock
)
1358 skb
= netlink_trim(skb
, gfp_any());
1360 timeo
= sock_sndtimeo(ssk
, nonblock
);
1362 sk
= netlink_getsockbyportid(ssk
, portid
);
1367 if (netlink_is_kernel(sk
))
1368 return netlink_unicast_kernel(sk
, skb
, ssk
);
1370 if (sk_filter(sk
, skb
)) {
1377 err
= netlink_attachskb(sk
, skb
, &timeo
, ssk
);
1383 return netlink_sendskb(sk
, skb
);
1385 EXPORT_SYMBOL(netlink_unicast
);
1387 int netlink_has_listeners(struct sock
*sk
, unsigned int group
)
1390 struct listeners
*listeners
;
1392 BUG_ON(!netlink_is_kernel(sk
));
1395 listeners
= rcu_dereference(nl_table
[sk
->sk_protocol
].listeners
);
1397 if (listeners
&& group
- 1 < nl_table
[sk
->sk_protocol
].groups
)
1398 res
= test_bit(group
- 1, listeners
->masks
);
1404 EXPORT_SYMBOL_GPL(netlink_has_listeners
);
1406 bool netlink_strict_get_check(struct sk_buff
*skb
)
1408 return nlk_test_bit(STRICT_CHK
, NETLINK_CB(skb
).sk
);
1410 EXPORT_SYMBOL_GPL(netlink_strict_get_check
);
1412 static int netlink_broadcast_deliver(struct sock
*sk
, struct sk_buff
*skb
)
1414 struct netlink_sock
*nlk
= nlk_sk(sk
);
1416 if (atomic_read(&sk
->sk_rmem_alloc
) <= sk
->sk_rcvbuf
&&
1417 !test_bit(NETLINK_S_CONGESTED
, &nlk
->state
)) {
1418 netlink_skb_set_owner_r(skb
, sk
);
1419 __netlink_sendskb(sk
, skb
);
1420 return atomic_read(&sk
->sk_rmem_alloc
) > (sk
->sk_rcvbuf
>> 1);
1425 struct netlink_broadcast_data
{
1426 struct sock
*exclude_sk
;
1431 int delivery_failure
;
1435 struct sk_buff
*skb
, *skb2
;
1436 int (*tx_filter
)(struct sock
*dsk
, struct sk_buff
*skb
, void *data
);
1440 static void do_one_broadcast(struct sock
*sk
,
1441 struct netlink_broadcast_data
*p
)
1443 struct netlink_sock
*nlk
= nlk_sk(sk
);
1446 if (p
->exclude_sk
== sk
)
1449 if (nlk
->portid
== p
->portid
|| p
->group
- 1 >= nlk
->ngroups
||
1450 !test_bit(p
->group
- 1, nlk
->groups
))
1453 if (!net_eq(sock_net(sk
), p
->net
)) {
1454 if (!nlk_test_bit(LISTEN_ALL_NSID
, sk
))
1457 if (!peernet_has_id(sock_net(sk
), p
->net
))
1460 if (!file_ns_capable(sk
->sk_socket
->file
, p
->net
->user_ns
,
1466 netlink_overrun(sk
);
1471 if (p
->skb2
== NULL
) {
1472 if (skb_shared(p
->skb
)) {
1473 p
->skb2
= skb_clone(p
->skb
, p
->allocation
);
1475 p
->skb2
= skb_get(p
->skb
);
1477 * skb ownership may have been set when
1478 * delivered to a previous socket.
1480 skb_orphan(p
->skb2
);
1483 if (p
->skb2
== NULL
) {
1484 netlink_overrun(sk
);
1485 /* Clone failed. Notify ALL listeners. */
1487 if (nlk_test_bit(BROADCAST_SEND_ERROR
, sk
))
1488 p
->delivery_failure
= 1;
1492 if (p
->tx_filter
&& p
->tx_filter(sk
, p
->skb2
, p
->tx_data
)) {
1498 if (sk_filter(sk
, p
->skb2
)) {
1503 NETLINK_CB(p
->skb2
).nsid
= peernet2id(sock_net(sk
), p
->net
);
1504 if (NETLINK_CB(p
->skb2
).nsid
!= NETNSA_NSID_NOT_ASSIGNED
)
1505 NETLINK_CB(p
->skb2
).nsid_is_set
= true;
1506 val
= netlink_broadcast_deliver(sk
, p
->skb2
);
1508 netlink_overrun(sk
);
1509 if (nlk_test_bit(BROADCAST_SEND_ERROR
, sk
))
1510 p
->delivery_failure
= 1;
1512 p
->congested
|= val
;
1520 int netlink_broadcast_filtered(struct sock
*ssk
, struct sk_buff
*skb
,
1522 u32 group
, gfp_t allocation
,
1523 int (*filter
)(struct sock
*dsk
,
1524 struct sk_buff
*skb
, void *data
),
1527 struct net
*net
= sock_net(ssk
);
1528 struct netlink_broadcast_data info
;
1531 skb
= netlink_trim(skb
, allocation
);
1533 info
.exclude_sk
= ssk
;
1535 info
.portid
= portid
;
1538 info
.delivery_failure
= 0;
1541 info
.allocation
= allocation
;
1544 info
.tx_filter
= filter
;
1545 info
.tx_data
= filter_data
;
1547 /* While we sleep in clone, do not allow to change socket list */
1549 netlink_lock_table();
1551 sk_for_each_bound(sk
, &nl_table
[ssk
->sk_protocol
].mc_list
)
1552 do_one_broadcast(sk
, &info
);
1556 netlink_unlock_table();
1558 if (info
.delivery_failure
) {
1559 kfree_skb(info
.skb2
);
1562 consume_skb(info
.skb2
);
1564 if (info
.delivered
) {
1565 if (info
.congested
&& gfpflags_allow_blocking(allocation
))
1571 EXPORT_SYMBOL(netlink_broadcast_filtered
);
1573 int netlink_broadcast(struct sock
*ssk
, struct sk_buff
*skb
, u32 portid
,
1574 u32 group
, gfp_t allocation
)
1576 return netlink_broadcast_filtered(ssk
, skb
, portid
, group
, allocation
,
1579 EXPORT_SYMBOL(netlink_broadcast
);
1581 struct netlink_set_err_data
{
1582 struct sock
*exclude_sk
;
1588 static int do_one_set_err(struct sock
*sk
, struct netlink_set_err_data
*p
)
1590 struct netlink_sock
*nlk
= nlk_sk(sk
);
1593 if (sk
== p
->exclude_sk
)
1596 if (!net_eq(sock_net(sk
), sock_net(p
->exclude_sk
)))
1599 if (nlk
->portid
== p
->portid
|| p
->group
- 1 >= nlk
->ngroups
||
1600 !test_bit(p
->group
- 1, nlk
->groups
))
1603 if (p
->code
== ENOBUFS
&& nlk_test_bit(RECV_NO_ENOBUFS
, sk
)) {
1608 WRITE_ONCE(sk
->sk_err
, p
->code
);
1609 sk_error_report(sk
);
1615 * netlink_set_err - report error to broadcast listeners
1616 * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
1617 * @portid: the PORTID of a process that we want to skip (if any)
1618 * @group: the broadcast group that will notice the error
1619 * @code: error code, must be negative (as usual in kernelspace)
1621 * This function returns the number of broadcast listeners that have set the
1622 * NETLINK_NO_ENOBUFS socket option.
1624 int netlink_set_err(struct sock
*ssk
, u32 portid
, u32 group
, int code
)
1626 struct netlink_set_err_data info
;
1627 unsigned long flags
;
1631 info
.exclude_sk
= ssk
;
1632 info
.portid
= portid
;
1634 /* sk->sk_err wants a positive error value */
1637 read_lock_irqsave(&nl_table_lock
, flags
);
1639 sk_for_each_bound(sk
, &nl_table
[ssk
->sk_protocol
].mc_list
)
1640 ret
+= do_one_set_err(sk
, &info
);
1642 read_unlock_irqrestore(&nl_table_lock
, flags
);
1645 EXPORT_SYMBOL(netlink_set_err
);
1647 /* must be called with netlink table grabbed */
1648 static void netlink_update_socket_mc(struct netlink_sock
*nlk
,
1652 int old
, new = !!is_new
, subscriptions
;
1654 old
= test_bit(group
- 1, nlk
->groups
);
1655 subscriptions
= nlk
->subscriptions
- old
+ new;
1656 __assign_bit(group
- 1, nlk
->groups
, new);
1657 netlink_update_subscriptions(&nlk
->sk
, subscriptions
);
1658 netlink_update_listeners(&nlk
->sk
);
1661 static int netlink_setsockopt(struct socket
*sock
, int level
, int optname
,
1662 sockptr_t optval
, unsigned int optlen
)
1664 struct sock
*sk
= sock
->sk
;
1665 struct netlink_sock
*nlk
= nlk_sk(sk
);
1666 unsigned int val
= 0;
1669 if (level
!= SOL_NETLINK
)
1670 return -ENOPROTOOPT
;
1672 if (optlen
>= sizeof(int) &&
1673 copy_from_sockptr(&val
, optval
, sizeof(val
)))
1677 case NETLINK_PKTINFO
:
1678 nr
= NETLINK_F_RECV_PKTINFO
;
1680 case NETLINK_ADD_MEMBERSHIP
:
1681 case NETLINK_DROP_MEMBERSHIP
: {
1684 if (!netlink_allowed(sock
, NL_CFG_F_NONROOT_RECV
))
1686 err
= netlink_realloc_groups(sk
);
1689 if (!val
|| val
- 1 >= nlk
->ngroups
)
1691 if (optname
== NETLINK_ADD_MEMBERSHIP
&& nlk
->netlink_bind
) {
1692 err
= nlk
->netlink_bind(sock_net(sk
), val
);
1696 netlink_table_grab();
1697 netlink_update_socket_mc(nlk
, val
,
1698 optname
== NETLINK_ADD_MEMBERSHIP
);
1699 netlink_table_ungrab();
1700 if (optname
== NETLINK_DROP_MEMBERSHIP
&& nlk
->netlink_unbind
)
1701 nlk
->netlink_unbind(sock_net(sk
), val
);
1705 case NETLINK_BROADCAST_ERROR
:
1706 nr
= NETLINK_F_BROADCAST_SEND_ERROR
;
1708 case NETLINK_NO_ENOBUFS
:
1709 assign_bit(NETLINK_F_RECV_NO_ENOBUFS
, &nlk
->flags
, val
);
1711 clear_bit(NETLINK_S_CONGESTED
, &nlk
->state
);
1712 wake_up_interruptible(&nlk
->wait
);
1715 case NETLINK_LISTEN_ALL_NSID
:
1716 if (!ns_capable(sock_net(sk
)->user_ns
, CAP_NET_BROADCAST
))
1718 nr
= NETLINK_F_LISTEN_ALL_NSID
;
1720 case NETLINK_CAP_ACK
:
1721 nr
= NETLINK_F_CAP_ACK
;
1723 case NETLINK_EXT_ACK
:
1724 nr
= NETLINK_F_EXT_ACK
;
1726 case NETLINK_GET_STRICT_CHK
:
1727 nr
= NETLINK_F_STRICT_CHK
;
1730 return -ENOPROTOOPT
;
1733 assign_bit(nr
, &nlk
->flags
, val
);
1737 static int netlink_getsockopt(struct socket
*sock
, int level
, int optname
,
1738 char __user
*optval
, int __user
*optlen
)
1740 struct sock
*sk
= sock
->sk
;
1741 struct netlink_sock
*nlk
= nlk_sk(sk
);
1745 if (level
!= SOL_NETLINK
)
1746 return -ENOPROTOOPT
;
1748 if (get_user(len
, optlen
))
1754 case NETLINK_PKTINFO
:
1755 flag
= NETLINK_F_RECV_PKTINFO
;
1757 case NETLINK_BROADCAST_ERROR
:
1758 flag
= NETLINK_F_BROADCAST_SEND_ERROR
;
1760 case NETLINK_NO_ENOBUFS
:
1761 flag
= NETLINK_F_RECV_NO_ENOBUFS
;
1763 case NETLINK_LIST_MEMBERSHIPS
: {
1764 int pos
, idx
, shift
, err
= 0;
1766 netlink_lock_table();
1767 for (pos
= 0; pos
* 8 < nlk
->ngroups
; pos
+= sizeof(u32
)) {
1768 if (len
- pos
< sizeof(u32
))
1771 idx
= pos
/ sizeof(unsigned long);
1772 shift
= (pos
% sizeof(unsigned long)) * 8;
1773 if (put_user((u32
)(nlk
->groups
[idx
] >> shift
),
1774 (u32 __user
*)(optval
+ pos
))) {
1779 if (put_user(ALIGN(BITS_TO_BYTES(nlk
->ngroups
), sizeof(u32
)), optlen
))
1781 netlink_unlock_table();
1784 case NETLINK_CAP_ACK
:
1785 flag
= NETLINK_F_CAP_ACK
;
1787 case NETLINK_EXT_ACK
:
1788 flag
= NETLINK_F_EXT_ACK
;
1790 case NETLINK_GET_STRICT_CHK
:
1791 flag
= NETLINK_F_STRICT_CHK
;
1794 return -ENOPROTOOPT
;
1797 if (len
< sizeof(int))
1801 val
= test_bit(flag
, &nlk
->flags
);
1803 if (put_user(len
, optlen
) ||
1804 copy_to_user(optval
, &val
, len
))
1810 static void netlink_cmsg_recv_pktinfo(struct msghdr
*msg
, struct sk_buff
*skb
)
1812 struct nl_pktinfo info
;
1814 info
.group
= NETLINK_CB(skb
).dst_group
;
1815 put_cmsg(msg
, SOL_NETLINK
, NETLINK_PKTINFO
, sizeof(info
), &info
);
1818 static void netlink_cmsg_listen_all_nsid(struct sock
*sk
, struct msghdr
*msg
,
1819 struct sk_buff
*skb
)
1821 if (!NETLINK_CB(skb
).nsid_is_set
)
1824 put_cmsg(msg
, SOL_NETLINK
, NETLINK_LISTEN_ALL_NSID
, sizeof(int),
1825 &NETLINK_CB(skb
).nsid
);
1828 static int netlink_sendmsg(struct socket
*sock
, struct msghdr
*msg
, size_t len
)
1830 struct sock
*sk
= sock
->sk
;
1831 struct netlink_sock
*nlk
= nlk_sk(sk
);
1832 DECLARE_SOCKADDR(struct sockaddr_nl
*, addr
, msg
->msg_name
);
1835 struct sk_buff
*skb
;
1837 struct scm_cookie scm
;
1838 u32 netlink_skb_flags
= 0;
1840 if (msg
->msg_flags
& MSG_OOB
)
1844 pr_warn_once("Zero length message leads to an empty skb\n");
1848 err
= scm_send(sock
, msg
, &scm
, true);
1852 if (msg
->msg_namelen
) {
1854 if (msg
->msg_namelen
< sizeof(struct sockaddr_nl
))
1856 if (addr
->nl_family
!= AF_NETLINK
)
1858 dst_portid
= addr
->nl_pid
;
1859 dst_group
= ffs(addr
->nl_groups
);
1861 if ((dst_group
|| dst_portid
) &&
1862 !netlink_allowed(sock
, NL_CFG_F_NONROOT_SEND
))
1864 netlink_skb_flags
|= NETLINK_SKB_DST
;
1866 /* Paired with WRITE_ONCE() in netlink_connect() */
1867 dst_portid
= READ_ONCE(nlk
->dst_portid
);
1868 dst_group
= READ_ONCE(nlk
->dst_group
);
1871 /* Paired with WRITE_ONCE() in netlink_insert() */
1872 if (!READ_ONCE(nlk
->bound
)) {
1873 err
= netlink_autobind(sock
);
1877 /* Ensure nlk is hashed and visible. */
1882 if (len
> sk
->sk_sndbuf
- 32)
1885 skb
= netlink_alloc_large_skb(len
, dst_group
);
1889 NETLINK_CB(skb
).portid
= nlk
->portid
;
1890 NETLINK_CB(skb
).dst_group
= dst_group
;
1891 NETLINK_CB(skb
).creds
= scm
.creds
;
1892 NETLINK_CB(skb
).flags
= netlink_skb_flags
;
1895 if (memcpy_from_msg(skb_put(skb
, len
), msg
, len
)) {
1900 err
= security_netlink_send(sk
, skb
);
1907 refcount_inc(&skb
->users
);
1908 netlink_broadcast(sk
, skb
, dst_portid
, dst_group
, GFP_KERNEL
);
1910 err
= netlink_unicast(sk
, skb
, dst_portid
, msg
->msg_flags
& MSG_DONTWAIT
);
1917 static int netlink_recvmsg(struct socket
*sock
, struct msghdr
*msg
, size_t len
,
1920 struct scm_cookie scm
;
1921 struct sock
*sk
= sock
->sk
;
1922 struct netlink_sock
*nlk
= nlk_sk(sk
);
1923 size_t copied
, max_recvmsg_len
;
1924 struct sk_buff
*skb
, *data_skb
;
1927 if (flags
& MSG_OOB
)
1932 skb
= skb_recv_datagram(sk
, flags
, &err
);
1938 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
1939 if (unlikely(skb_shinfo(skb
)->frag_list
)) {
1941 * If this skb has a frag_list, then here that means that we
1942 * will have to use the frag_list skb's data for compat tasks
1943 * and the regular skb's data for normal (non-compat) tasks.
1945 * If we need to send the compat skb, assign it to the
1946 * 'data_skb' variable so that it will be used below for data
1947 * copying. We keep 'skb' for everything else, including
1948 * freeing both later.
1950 if (flags
& MSG_CMSG_COMPAT
)
1951 data_skb
= skb_shinfo(skb
)->frag_list
;
1955 /* Record the max length of recvmsg() calls for future allocations */
1956 max_recvmsg_len
= max(READ_ONCE(nlk
->max_recvmsg_len
), len
);
1957 max_recvmsg_len
= min_t(size_t, max_recvmsg_len
,
1958 SKB_WITH_OVERHEAD(32768));
1959 WRITE_ONCE(nlk
->max_recvmsg_len
, max_recvmsg_len
);
1961 copied
= data_skb
->len
;
1963 msg
->msg_flags
|= MSG_TRUNC
;
1967 err
= skb_copy_datagram_msg(data_skb
, 0, msg
, copied
);
1969 if (msg
->msg_name
) {
1970 DECLARE_SOCKADDR(struct sockaddr_nl
*, addr
, msg
->msg_name
);
1971 addr
->nl_family
= AF_NETLINK
;
1973 addr
->nl_pid
= NETLINK_CB(skb
).portid
;
1974 addr
->nl_groups
= netlink_group_mask(NETLINK_CB(skb
).dst_group
);
1975 msg
->msg_namelen
= sizeof(*addr
);
1978 if (nlk_test_bit(RECV_PKTINFO
, sk
))
1979 netlink_cmsg_recv_pktinfo(msg
, skb
);
1980 if (nlk_test_bit(LISTEN_ALL_NSID
, sk
))
1981 netlink_cmsg_listen_all_nsid(sk
, msg
, skb
);
1983 memset(&scm
, 0, sizeof(scm
));
1984 scm
.creds
= *NETLINK_CREDS(skb
);
1985 if (flags
& MSG_TRUNC
)
1986 copied
= data_skb
->len
;
1988 skb_free_datagram(sk
, skb
);
1990 if (READ_ONCE(nlk
->cb_running
) &&
1991 atomic_read(&sk
->sk_rmem_alloc
) <= sk
->sk_rcvbuf
/ 2) {
1992 ret
= netlink_dump(sk
);
1994 WRITE_ONCE(sk
->sk_err
, -ret
);
1995 sk_error_report(sk
);
1999 scm_recv(sock
, msg
, &scm
, flags
);
2001 netlink_rcv_wake(sk
);
2002 return err
? : copied
;
2005 static void netlink_data_ready(struct sock
*sk
)
2011 * We export these functions to other modules. They provide a
2012 * complete set of kernel non-blocking support for message
2017 __netlink_kernel_create(struct net
*net
, int unit
, struct module
*module
,
2018 struct netlink_kernel_cfg
*cfg
)
2020 struct socket
*sock
;
2022 struct netlink_sock
*nlk
;
2023 struct listeners
*listeners
= NULL
;
2024 struct mutex
*cb_mutex
= cfg
? cfg
->cb_mutex
: NULL
;
2025 unsigned int groups
;
2029 if (unit
< 0 || unit
>= MAX_LINKS
)
2032 if (sock_create_lite(PF_NETLINK
, SOCK_DGRAM
, unit
, &sock
))
2035 if (__netlink_create(net
, sock
, cb_mutex
, unit
, 1) < 0)
2036 goto out_sock_release_nosk
;
2040 if (!cfg
|| cfg
->groups
< 32)
2043 groups
= cfg
->groups
;
2045 listeners
= kzalloc(sizeof(*listeners
) + NLGRPSZ(groups
), GFP_KERNEL
);
2047 goto out_sock_release
;
2049 sk
->sk_data_ready
= netlink_data_ready
;
2050 if (cfg
&& cfg
->input
)
2051 nlk_sk(sk
)->netlink_rcv
= cfg
->input
;
2053 if (netlink_insert(sk
, 0))
2054 goto out_sock_release
;
2057 set_bit(NETLINK_F_KERNEL_SOCKET
, &nlk
->flags
);
2059 netlink_table_grab();
2060 if (!nl_table
[unit
].registered
) {
2061 nl_table
[unit
].groups
= groups
;
2062 rcu_assign_pointer(nl_table
[unit
].listeners
, listeners
);
2063 nl_table
[unit
].cb_mutex
= cb_mutex
;
2064 nl_table
[unit
].module
= module
;
2066 nl_table
[unit
].bind
= cfg
->bind
;
2067 nl_table
[unit
].unbind
= cfg
->unbind
;
2068 nl_table
[unit
].release
= cfg
->release
;
2069 nl_table
[unit
].flags
= cfg
->flags
;
2071 nl_table
[unit
].registered
= 1;
2074 nl_table
[unit
].registered
++;
2076 netlink_table_ungrab();
2081 netlink_kernel_release(sk
);
2084 out_sock_release_nosk
:
2088 EXPORT_SYMBOL(__netlink_kernel_create
);
2091 netlink_kernel_release(struct sock
*sk
)
2093 if (sk
== NULL
|| sk
->sk_socket
== NULL
)
2096 sock_release(sk
->sk_socket
);
2098 EXPORT_SYMBOL(netlink_kernel_release
);
2100 int __netlink_change_ngroups(struct sock
*sk
, unsigned int groups
)
2102 struct listeners
*new, *old
;
2103 struct netlink_table
*tbl
= &nl_table
[sk
->sk_protocol
];
2108 if (NLGRPSZ(tbl
->groups
) < NLGRPSZ(groups
)) {
2109 new = kzalloc(sizeof(*new) + NLGRPSZ(groups
), GFP_ATOMIC
);
2112 old
= nl_deref_protected(tbl
->listeners
);
2113 memcpy(new->masks
, old
->masks
, NLGRPSZ(tbl
->groups
));
2114 rcu_assign_pointer(tbl
->listeners
, new);
2116 kfree_rcu(old
, rcu
);
2118 tbl
->groups
= groups
;
2124 * netlink_change_ngroups - change number of multicast groups
2126 * This changes the number of multicast groups that are available
2127 * on a certain netlink family. Note that it is not possible to
2128 * change the number of groups to below 32. Also note that it does
2129 * not implicitly call netlink_clear_multicast_users() when the
2130 * number of groups is reduced.
2132 * @sk: The kernel netlink socket, as returned by netlink_kernel_create().
2133 * @groups: The new number of groups.
2135 int netlink_change_ngroups(struct sock
*sk
, unsigned int groups
)
2139 netlink_table_grab();
2140 err
= __netlink_change_ngroups(sk
, groups
);
2141 netlink_table_ungrab();
2146 void __netlink_clear_multicast_users(struct sock
*ksk
, unsigned int group
)
2149 struct netlink_table
*tbl
= &nl_table
[ksk
->sk_protocol
];
2151 sk_for_each_bound(sk
, &tbl
->mc_list
)
2152 netlink_update_socket_mc(nlk_sk(sk
), group
, 0);
2156 __nlmsg_put(struct sk_buff
*skb
, u32 portid
, u32 seq
, int type
, int len
, int flags
)
2158 struct nlmsghdr
*nlh
;
2159 int size
= nlmsg_msg_size(len
);
2161 nlh
= skb_put(skb
, NLMSG_ALIGN(size
));
2162 nlh
->nlmsg_type
= type
;
2163 nlh
->nlmsg_len
= size
;
2164 nlh
->nlmsg_flags
= flags
;
2165 nlh
->nlmsg_pid
= portid
;
2166 nlh
->nlmsg_seq
= seq
;
2167 if (!__builtin_constant_p(size
) || NLMSG_ALIGN(size
) - size
!= 0)
2168 memset(nlmsg_data(nlh
) + len
, 0, NLMSG_ALIGN(size
) - size
);
2171 EXPORT_SYMBOL(__nlmsg_put
);
2174 * It looks a bit ugly.
2175 * It would be better to create kernel thread.
2178 static int netlink_dump_done(struct netlink_sock
*nlk
, struct sk_buff
*skb
,
2179 struct netlink_callback
*cb
,
2180 struct netlink_ext_ack
*extack
)
2182 struct nlmsghdr
*nlh
;
2184 nlh
= nlmsg_put_answer(skb
, cb
, NLMSG_DONE
, sizeof(nlk
->dump_done_errno
),
2185 NLM_F_MULTI
| cb
->answer_flags
);
2189 nl_dump_check_consistent(cb
, nlh
);
2190 memcpy(nlmsg_data(nlh
), &nlk
->dump_done_errno
, sizeof(nlk
->dump_done_errno
));
2192 if (extack
->_msg
&& test_bit(NETLINK_F_EXT_ACK
, &nlk
->flags
)) {
2193 nlh
->nlmsg_flags
|= NLM_F_ACK_TLVS
;
2194 if (!nla_put_string(skb
, NLMSGERR_ATTR_MSG
, extack
->_msg
))
2195 nlmsg_end(skb
, nlh
);
2201 static int netlink_dump(struct sock
*sk
)
2203 struct netlink_sock
*nlk
= nlk_sk(sk
);
2204 struct netlink_ext_ack extack
= {};
2205 struct netlink_callback
*cb
;
2206 struct sk_buff
*skb
= NULL
;
2207 size_t max_recvmsg_len
;
2208 struct module
*module
;
2213 mutex_lock(nlk
->cb_mutex
);
2214 if (!nlk
->cb_running
) {
2219 if (atomic_read(&sk
->sk_rmem_alloc
) >= sk
->sk_rcvbuf
)
2222 /* NLMSG_GOODSIZE is small to avoid high order allocations being
2223 * required, but it makes sense to _attempt_ a 16K bytes allocation
2224 * to reduce number of system calls on dump operations, if user
2225 * ever provided a big enough buffer.
2228 alloc_min_size
= max_t(int, cb
->min_dump_alloc
, NLMSG_GOODSIZE
);
2230 max_recvmsg_len
= READ_ONCE(nlk
->max_recvmsg_len
);
2231 if (alloc_min_size
< max_recvmsg_len
) {
2232 alloc_size
= max_recvmsg_len
;
2233 skb
= alloc_skb(alloc_size
,
2234 (GFP_KERNEL
& ~__GFP_DIRECT_RECLAIM
) |
2235 __GFP_NOWARN
| __GFP_NORETRY
);
2238 alloc_size
= alloc_min_size
;
2239 skb
= alloc_skb(alloc_size
, GFP_KERNEL
);
2244 /* Trim skb to allocated size. User is expected to provide buffer as
2245 * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at
2246 * netlink_recvmsg())). dump will pack as many smaller messages as
2247 * could fit within the allocated skb. skb is typically allocated
2248 * with larger space than required (could be as much as near 2x the
2249 * requested size with align to next power of 2 approach). Allowing
2250 * dump to use the excess space makes it difficult for a user to have a
2251 * reasonable static buffer based on the expected largest dump of a
2252 * single netdev. The outcome is MSG_TRUNC error.
2254 skb_reserve(skb
, skb_tailroom(skb
) - alloc_size
);
2256 /* Make sure malicious BPF programs can not read unitialized memory
2257 * from skb->head -> skb->data
2259 skb_reset_network_header(skb
);
2260 skb_reset_mac_header(skb
);
2262 netlink_skb_set_owner_r(skb
, sk
);
2264 if (nlk
->dump_done_errno
> 0) {
2265 cb
->extack
= &extack
;
2266 nlk
->dump_done_errno
= cb
->dump(skb
, cb
);
2270 if (nlk
->dump_done_errno
> 0 ||
2271 skb_tailroom(skb
) < nlmsg_total_size(sizeof(nlk
->dump_done_errno
))) {
2272 mutex_unlock(nlk
->cb_mutex
);
2274 if (sk_filter(sk
, skb
))
2277 __netlink_sendskb(sk
, skb
);
2281 if (netlink_dump_done(nlk
, skb
, cb
, &extack
))
2284 #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
2285 /* frag_list skb's data is used for compat tasks
2286 * and the regular skb's data for normal (non-compat) tasks.
2287 * See netlink_recvmsg().
2289 if (unlikely(skb_shinfo(skb
)->frag_list
)) {
2290 if (netlink_dump_done(nlk
, skb_shinfo(skb
)->frag_list
, cb
, &extack
))
2295 if (sk_filter(sk
, skb
))
2298 __netlink_sendskb(sk
, skb
);
2303 WRITE_ONCE(nlk
->cb_running
, false);
2304 module
= cb
->module
;
2306 mutex_unlock(nlk
->cb_mutex
);
2312 mutex_unlock(nlk
->cb_mutex
);
2317 int __netlink_dump_start(struct sock
*ssk
, struct sk_buff
*skb
,
2318 const struct nlmsghdr
*nlh
,
2319 struct netlink_dump_control
*control
)
2321 struct netlink_callback
*cb
;
2322 struct netlink_sock
*nlk
;
2326 refcount_inc(&skb
->users
);
2328 sk
= netlink_lookup(sock_net(ssk
), ssk
->sk_protocol
, NETLINK_CB(skb
).portid
);
2330 ret
= -ECONNREFUSED
;
2335 mutex_lock(nlk
->cb_mutex
);
2336 /* A dump is in progress... */
2337 if (nlk
->cb_running
) {
2341 /* add reference of module which cb->dump belongs to */
2342 if (!try_module_get(control
->module
)) {
2343 ret
= -EPROTONOSUPPORT
;
2348 memset(cb
, 0, sizeof(*cb
));
2349 cb
->dump
= control
->dump
;
2350 cb
->done
= control
->done
;
2352 cb
->data
= control
->data
;
2353 cb
->module
= control
->module
;
2354 cb
->min_dump_alloc
= control
->min_dump_alloc
;
2357 cb
->strict_check
= nlk_test_bit(STRICT_CHK
, NETLINK_CB(skb
).sk
);
2359 if (control
->start
) {
2360 cb
->extack
= control
->extack
;
2361 ret
= control
->start(cb
);
2367 WRITE_ONCE(nlk
->cb_running
, true);
2368 nlk
->dump_done_errno
= INT_MAX
;
2370 mutex_unlock(nlk
->cb_mutex
);
2372 ret
= netlink_dump(sk
);
2379 /* We successfully started a dump, by returning -EINTR we
2380 * signal not to send ACK even if it was requested.
2385 module_put(control
->module
);
2388 mutex_unlock(nlk
->cb_mutex
);
2393 EXPORT_SYMBOL(__netlink_dump_start
);
2396 netlink_ack_tlv_len(struct netlink_sock
*nlk
, int err
,
2397 const struct netlink_ext_ack
*extack
)
2401 if (!extack
|| !test_bit(NETLINK_F_EXT_ACK
, &nlk
->flags
))
2406 tlvlen
+= nla_total_size(strlen(extack
->_msg
) + 1);
2407 if (extack
->cookie_len
)
2408 tlvlen
+= nla_total_size(extack
->cookie_len
);
2410 /* Following attributes are only reported as error (not warning) */
2414 if (extack
->bad_attr
)
2415 tlvlen
+= nla_total_size(sizeof(u32
));
2417 tlvlen
+= netlink_policy_dump_attr_size_estimate(extack
->policy
);
2418 if (extack
->miss_type
)
2419 tlvlen
+= nla_total_size(sizeof(u32
));
2420 if (extack
->miss_nest
)
2421 tlvlen
+= nla_total_size(sizeof(u32
));
2427 netlink_ack_tlv_fill(struct sk_buff
*in_skb
, struct sk_buff
*skb
,
2428 struct nlmsghdr
*nlh
, int err
,
2429 const struct netlink_ext_ack
*extack
)
2432 WARN_ON(nla_put_string(skb
, NLMSGERR_ATTR_MSG
, extack
->_msg
));
2433 if (extack
->cookie_len
)
2434 WARN_ON(nla_put(skb
, NLMSGERR_ATTR_COOKIE
,
2435 extack
->cookie_len
, extack
->cookie
));
2440 if (extack
->bad_attr
&&
2441 !WARN_ON((u8
*)extack
->bad_attr
< in_skb
->data
||
2442 (u8
*)extack
->bad_attr
>= in_skb
->data
+ in_skb
->len
))
2443 WARN_ON(nla_put_u32(skb
, NLMSGERR_ATTR_OFFS
,
2444 (u8
*)extack
->bad_attr
- (u8
*)nlh
));
2446 netlink_policy_dump_write_attr(skb
, extack
->policy
,
2447 NLMSGERR_ATTR_POLICY
);
2448 if (extack
->miss_type
)
2449 WARN_ON(nla_put_u32(skb
, NLMSGERR_ATTR_MISS_TYPE
,
2450 extack
->miss_type
));
2451 if (extack
->miss_nest
&&
2452 !WARN_ON((u8
*)extack
->miss_nest
< in_skb
->data
||
2453 (u8
*)extack
->miss_nest
> in_skb
->data
+ in_skb
->len
))
2454 WARN_ON(nla_put_u32(skb
, NLMSGERR_ATTR_MISS_NEST
,
2455 (u8
*)extack
->miss_nest
- (u8
*)nlh
));
2458 void netlink_ack(struct sk_buff
*in_skb
, struct nlmsghdr
*nlh
, int err
,
2459 const struct netlink_ext_ack
*extack
)
2461 struct sk_buff
*skb
;
2462 struct nlmsghdr
*rep
;
2463 struct nlmsgerr
*errmsg
;
2464 size_t payload
= sizeof(*errmsg
);
2465 struct netlink_sock
*nlk
= nlk_sk(NETLINK_CB(in_skb
).sk
);
2466 unsigned int flags
= 0;
2469 /* Error messages get the original request appened, unless the user
2470 * requests to cap the error message, and get extra error data if
2473 if (err
&& !test_bit(NETLINK_F_CAP_ACK
, &nlk
->flags
))
2474 payload
+= nlmsg_len(nlh
);
2476 flags
|= NLM_F_CAPPED
;
2478 tlvlen
= netlink_ack_tlv_len(nlk
, err
, extack
);
2480 flags
|= NLM_F_ACK_TLVS
;
2482 skb
= nlmsg_new(payload
+ tlvlen
, GFP_KERNEL
);
2486 rep
= nlmsg_put(skb
, NETLINK_CB(in_skb
).portid
, nlh
->nlmsg_seq
,
2487 NLMSG_ERROR
, sizeof(*errmsg
), flags
);
2490 errmsg
= nlmsg_data(rep
);
2491 errmsg
->error
= err
;
2494 if (!(flags
& NLM_F_CAPPED
)) {
2495 if (!nlmsg_append(skb
, nlmsg_len(nlh
)))
2498 memcpy(nlmsg_data(&errmsg
->msg
), nlmsg_data(nlh
),
2503 netlink_ack_tlv_fill(in_skb
, skb
, nlh
, err
, extack
);
2505 nlmsg_end(skb
, rep
);
2507 nlmsg_unicast(in_skb
->sk
, skb
, NETLINK_CB(in_skb
).portid
);
2514 WRITE_ONCE(NETLINK_CB(in_skb
).sk
->sk_err
, ENOBUFS
);
2515 sk_error_report(NETLINK_CB(in_skb
).sk
);
2517 EXPORT_SYMBOL(netlink_ack
);
2519 int netlink_rcv_skb(struct sk_buff
*skb
, int (*cb
)(struct sk_buff
*,
2521 struct netlink_ext_ack
*))
2523 struct netlink_ext_ack extack
;
2524 struct nlmsghdr
*nlh
;
2527 while (skb
->len
>= nlmsg_total_size(0)) {
2530 memset(&extack
, 0, sizeof(extack
));
2531 nlh
= nlmsg_hdr(skb
);
2534 if (nlh
->nlmsg_len
< NLMSG_HDRLEN
|| skb
->len
< nlh
->nlmsg_len
)
2537 /* Only requests are handled by the kernel */
2538 if (!(nlh
->nlmsg_flags
& NLM_F_REQUEST
))
2541 /* Skip control messages */
2542 if (nlh
->nlmsg_type
< NLMSG_MIN_TYPE
)
2545 err
= cb(skb
, nlh
, &extack
);
2550 if (nlh
->nlmsg_flags
& NLM_F_ACK
|| err
)
2551 netlink_ack(skb
, nlh
, err
, &extack
);
2554 msglen
= NLMSG_ALIGN(nlh
->nlmsg_len
);
2555 if (msglen
> skb
->len
)
2557 skb_pull(skb
, msglen
);
2562 EXPORT_SYMBOL(netlink_rcv_skb
);
2565 * nlmsg_notify - send a notification netlink message
2566 * @sk: netlink socket to use
2567 * @skb: notification message
2568 * @portid: destination netlink portid for reports or 0
2569 * @group: destination multicast group or 0
2570 * @report: 1 to report back, 0 to disable
2571 * @flags: allocation flags
2573 int nlmsg_notify(struct sock
*sk
, struct sk_buff
*skb
, u32 portid
,
2574 unsigned int group
, int report
, gfp_t flags
)
2579 int exclude_portid
= 0;
2582 refcount_inc(&skb
->users
);
2583 exclude_portid
= portid
;
2586 /* errors reported via destination sk->sk_err, but propagate
2587 * delivery errors if NETLINK_BROADCAST_ERROR flag is set */
2588 err
= nlmsg_multicast(sk
, skb
, exclude_portid
, group
, flags
);
2596 err2
= nlmsg_unicast(sk
, skb
, portid
);
2603 EXPORT_SYMBOL(nlmsg_notify
);
2605 #ifdef CONFIG_PROC_FS
2606 struct nl_seq_iter
{
2607 struct seq_net_private p
;
2608 struct rhashtable_iter hti
;
2612 static void netlink_walk_start(struct nl_seq_iter
*iter
)
2614 rhashtable_walk_enter(&nl_table
[iter
->link
].hash
, &iter
->hti
);
2615 rhashtable_walk_start(&iter
->hti
);
2618 static void netlink_walk_stop(struct nl_seq_iter
*iter
)
2620 rhashtable_walk_stop(&iter
->hti
);
2621 rhashtable_walk_exit(&iter
->hti
);
2624 static void *__netlink_seq_next(struct seq_file
*seq
)
2626 struct nl_seq_iter
*iter
= seq
->private;
2627 struct netlink_sock
*nlk
;
2631 nlk
= rhashtable_walk_next(&iter
->hti
);
2634 if (PTR_ERR(nlk
) == -EAGAIN
)
2643 netlink_walk_stop(iter
);
2644 if (++iter
->link
>= MAX_LINKS
)
2647 netlink_walk_start(iter
);
2649 } while (sock_net(&nlk
->sk
) != seq_file_net(seq
));
2654 static void *netlink_seq_start(struct seq_file
*seq
, loff_t
*posp
)
2657 struct nl_seq_iter
*iter
= seq
->private;
2658 void *obj
= SEQ_START_TOKEN
;
2663 netlink_walk_start(iter
);
2665 for (pos
= *posp
; pos
&& obj
&& !IS_ERR(obj
); pos
--)
2666 obj
= __netlink_seq_next(seq
);
2671 static void *netlink_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
2674 return __netlink_seq_next(seq
);
2677 static void netlink_native_seq_stop(struct seq_file
*seq
, void *v
)
2679 struct nl_seq_iter
*iter
= seq
->private;
2681 if (iter
->link
>= MAX_LINKS
)
2684 netlink_walk_stop(iter
);
2688 static int netlink_native_seq_show(struct seq_file
*seq
, void *v
)
2690 if (v
== SEQ_START_TOKEN
) {
2692 "sk Eth Pid Groups "
2693 "Rmem Wmem Dump Locks Drops Inode\n");
2696 struct netlink_sock
*nlk
= nlk_sk(s
);
2698 seq_printf(seq
, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8u %-8lu\n",
2702 nlk
->groups
? (u32
)nlk
->groups
[0] : 0,
2703 sk_rmem_alloc_get(s
),
2704 sk_wmem_alloc_get(s
),
2705 READ_ONCE(nlk
->cb_running
),
2706 refcount_read(&s
->sk_refcnt
),
2707 atomic_read(&s
->sk_drops
),
2715 #ifdef CONFIG_BPF_SYSCALL
2716 struct bpf_iter__netlink
{
2717 __bpf_md_ptr(struct bpf_iter_meta
*, meta
);
2718 __bpf_md_ptr(struct netlink_sock
*, sk
);
2721 DEFINE_BPF_ITER_FUNC(netlink
, struct bpf_iter_meta
*meta
, struct netlink_sock
*sk
)
2723 static int netlink_prog_seq_show(struct bpf_prog
*prog
,
2724 struct bpf_iter_meta
*meta
,
2727 struct bpf_iter__netlink ctx
;
2729 meta
->seq_num
--; /* skip SEQ_START_TOKEN */
2731 ctx
.sk
= nlk_sk((struct sock
*)v
);
2732 return bpf_iter_run_prog(prog
, &ctx
);
2735 static int netlink_seq_show(struct seq_file
*seq
, void *v
)
2737 struct bpf_iter_meta meta
;
2738 struct bpf_prog
*prog
;
2741 prog
= bpf_iter_get_info(&meta
, false);
2743 return netlink_native_seq_show(seq
, v
);
2745 if (v
!= SEQ_START_TOKEN
)
2746 return netlink_prog_seq_show(prog
, &meta
, v
);
2751 static void netlink_seq_stop(struct seq_file
*seq
, void *v
)
2753 struct bpf_iter_meta meta
;
2754 struct bpf_prog
*prog
;
2758 prog
= bpf_iter_get_info(&meta
, true);
2760 (void)netlink_prog_seq_show(prog
, &meta
, v
);
2763 netlink_native_seq_stop(seq
, v
);
2766 static int netlink_seq_show(struct seq_file
*seq
, void *v
)
2768 return netlink_native_seq_show(seq
, v
);
2771 static void netlink_seq_stop(struct seq_file
*seq
, void *v
)
2773 netlink_native_seq_stop(seq
, v
);
2777 static const struct seq_operations netlink_seq_ops
= {
2778 .start
= netlink_seq_start
,
2779 .next
= netlink_seq_next
,
2780 .stop
= netlink_seq_stop
,
2781 .show
= netlink_seq_show
,
2785 int netlink_register_notifier(struct notifier_block
*nb
)
2787 return blocking_notifier_chain_register(&netlink_chain
, nb
);
2789 EXPORT_SYMBOL(netlink_register_notifier
);
2791 int netlink_unregister_notifier(struct notifier_block
*nb
)
2793 return blocking_notifier_chain_unregister(&netlink_chain
, nb
);
2795 EXPORT_SYMBOL(netlink_unregister_notifier
);
2797 static const struct proto_ops netlink_ops
= {
2798 .family
= PF_NETLINK
,
2799 .owner
= THIS_MODULE
,
2800 .release
= netlink_release
,
2801 .bind
= netlink_bind
,
2802 .connect
= netlink_connect
,
2803 .socketpair
= sock_no_socketpair
,
2804 .accept
= sock_no_accept
,
2805 .getname
= netlink_getname
,
2806 .poll
= datagram_poll
,
2807 .ioctl
= netlink_ioctl
,
2808 .listen
= sock_no_listen
,
2809 .shutdown
= sock_no_shutdown
,
2810 .setsockopt
= netlink_setsockopt
,
2811 .getsockopt
= netlink_getsockopt
,
2812 .sendmsg
= netlink_sendmsg
,
2813 .recvmsg
= netlink_recvmsg
,
2814 .mmap
= sock_no_mmap
,
2817 static const struct net_proto_family netlink_family_ops
= {
2818 .family
= PF_NETLINK
,
2819 .create
= netlink_create
,
2820 .owner
= THIS_MODULE
, /* for consistency 8) */
2823 static int __net_init
netlink_net_init(struct net
*net
)
2825 #ifdef CONFIG_PROC_FS
2826 if (!proc_create_net("netlink", 0, net
->proc_net
, &netlink_seq_ops
,
2827 sizeof(struct nl_seq_iter
)))
2833 static void __net_exit
netlink_net_exit(struct net
*net
)
2835 #ifdef CONFIG_PROC_FS
2836 remove_proc_entry("netlink", net
->proc_net
);
2840 static void __init
netlink_add_usersock_entry(void)
2842 struct listeners
*listeners
;
2845 listeners
= kzalloc(sizeof(*listeners
) + NLGRPSZ(groups
), GFP_KERNEL
);
2847 panic("netlink_add_usersock_entry: Cannot allocate listeners\n");
2849 netlink_table_grab();
2851 nl_table
[NETLINK_USERSOCK
].groups
= groups
;
2852 rcu_assign_pointer(nl_table
[NETLINK_USERSOCK
].listeners
, listeners
);
2853 nl_table
[NETLINK_USERSOCK
].module
= THIS_MODULE
;
2854 nl_table
[NETLINK_USERSOCK
].registered
= 1;
2855 nl_table
[NETLINK_USERSOCK
].flags
= NL_CFG_F_NONROOT_SEND
;
2857 netlink_table_ungrab();
2860 static struct pernet_operations __net_initdata netlink_net_ops
= {
2861 .init
= netlink_net_init
,
2862 .exit
= netlink_net_exit
,
2865 static inline u32
netlink_hash(const void *data
, u32 len
, u32 seed
)
2867 const struct netlink_sock
*nlk
= data
;
2868 struct netlink_compare_arg arg
;
2870 netlink_compare_arg_init(&arg
, sock_net(&nlk
->sk
), nlk
->portid
);
2871 return jhash2((u32
*)&arg
, netlink_compare_arg_len
/ sizeof(u32
), seed
);
2874 static const struct rhashtable_params netlink_rhashtable_params
= {
2875 .head_offset
= offsetof(struct netlink_sock
, node
),
2876 .key_len
= netlink_compare_arg_len
,
2877 .obj_hashfn
= netlink_hash
,
2878 .obj_cmpfn
= netlink_compare
,
2879 .automatic_shrinking
= true,
2882 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2883 BTF_ID_LIST(btf_netlink_sock_id
)
2884 BTF_ID(struct, netlink_sock
)
2886 static const struct bpf_iter_seq_info netlink_seq_info
= {
2887 .seq_ops
= &netlink_seq_ops
,
2888 .init_seq_private
= bpf_iter_init_seq_net
,
2889 .fini_seq_private
= bpf_iter_fini_seq_net
,
2890 .seq_priv_size
= sizeof(struct nl_seq_iter
),
2893 static struct bpf_iter_reg netlink_reg_info
= {
2894 .target
= "netlink",
2895 .ctx_arg_info_size
= 1,
2897 { offsetof(struct bpf_iter__netlink
, sk
),
2898 PTR_TO_BTF_ID_OR_NULL
},
2900 .seq_info
= &netlink_seq_info
,
2903 static int __init
bpf_iter_register(void)
2905 netlink_reg_info
.ctx_arg_info
[0].btf_id
= *btf_netlink_sock_id
;
2906 return bpf_iter_reg_target(&netlink_reg_info
);
2910 static int __init
netlink_proto_init(void)
2913 int err
= proto_register(&netlink_proto
, 0);
2918 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)
2919 err
= bpf_iter_register();
2924 BUILD_BUG_ON(sizeof(struct netlink_skb_parms
) > sizeof_field(struct sk_buff
, cb
));
2926 nl_table
= kcalloc(MAX_LINKS
, sizeof(*nl_table
), GFP_KERNEL
);
2930 for (i
= 0; i
< MAX_LINKS
; i
++) {
2931 if (rhashtable_init(&nl_table
[i
].hash
,
2932 &netlink_rhashtable_params
) < 0) {
2934 rhashtable_destroy(&nl_table
[i
].hash
);
2940 netlink_add_usersock_entry();
2942 sock_register(&netlink_family_ops
);
2943 register_pernet_subsys(&netlink_net_ops
);
2944 register_pernet_subsys(&netlink_tap_net_ops
);
2945 /* The netlink device handler may be needed early. */
2950 panic("netlink_init: Cannot allocate nl_table\n");
2953 core_initcall(netlink_proto_init
);