/net/netlink/af_netlink.c
http://github.com/mirrors/linux · C · 2780 lines · 2127 code · 449 blank · 204 comment · 393 complexity · 517b2a5492a812d872ac4822651117e8 MD5 · raw file
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- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * NETLINK Kernel-user communication protocol.
- *
- * Authors: Alan Cox <alan@lxorguk.ukuu.org.uk>
- * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
- * Patrick McHardy <kaber@trash.net>
- *
- * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
- * added netlink_proto_exit
- * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
- * use nlk_sk, as sk->protinfo is on a diet 8)
- * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
- * - inc module use count of module that owns
- * the kernel socket in case userspace opens
- * socket of same protocol
- * - remove all module support, since netlink is
- * mandatory if CONFIG_NET=y these days
- */
- #include <linux/module.h>
- #include <linux/capability.h>
- #include <linux/kernel.h>
- #include <linux/init.h>
- #include <linux/signal.h>
- #include <linux/sched.h>
- #include <linux/errno.h>
- #include <linux/string.h>
- #include <linux/stat.h>
- #include <linux/socket.h>
- #include <linux/un.h>
- #include <linux/fcntl.h>
- #include <linux/termios.h>
- #include <linux/sockios.h>
- #include <linux/net.h>
- #include <linux/fs.h>
- #include <linux/slab.h>
- #include <linux/uaccess.h>
- #include <linux/skbuff.h>
- #include <linux/netdevice.h>
- #include <linux/rtnetlink.h>
- #include <linux/proc_fs.h>
- #include <linux/seq_file.h>
- #include <linux/notifier.h>
- #include <linux/security.h>
- #include <linux/jhash.h>
- #include <linux/jiffies.h>
- #include <linux/random.h>
- #include <linux/bitops.h>
- #include <linux/mm.h>
- #include <linux/types.h>
- #include <linux/audit.h>
- #include <linux/mutex.h>
- #include <linux/vmalloc.h>
- #include <linux/if_arp.h>
- #include <linux/rhashtable.h>
- #include <asm/cacheflush.h>
- #include <linux/hash.h>
- #include <linux/genetlink.h>
- #include <linux/net_namespace.h>
- #include <linux/nospec.h>
- #include <net/net_namespace.h>
- #include <net/netns/generic.h>
- #include <net/sock.h>
- #include <net/scm.h>
- #include <net/netlink.h>
- #include "af_netlink.h"
- struct listeners {
- struct rcu_head rcu;
- unsigned long masks[];
- };
- /* state bits */
- #define NETLINK_S_CONGESTED 0x0
- static inline int netlink_is_kernel(struct sock *sk)
- {
- return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;
- }
- struct netlink_table *nl_table __read_mostly;
- EXPORT_SYMBOL_GPL(nl_table);
- static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
- static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
- static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
- "nlk_cb_mutex-ROUTE",
- "nlk_cb_mutex-1",
- "nlk_cb_mutex-USERSOCK",
- "nlk_cb_mutex-FIREWALL",
- "nlk_cb_mutex-SOCK_DIAG",
- "nlk_cb_mutex-NFLOG",
- "nlk_cb_mutex-XFRM",
- "nlk_cb_mutex-SELINUX",
- "nlk_cb_mutex-ISCSI",
- "nlk_cb_mutex-AUDIT",
- "nlk_cb_mutex-FIB_LOOKUP",
- "nlk_cb_mutex-CONNECTOR",
- "nlk_cb_mutex-NETFILTER",
- "nlk_cb_mutex-IP6_FW",
- "nlk_cb_mutex-DNRTMSG",
- "nlk_cb_mutex-KOBJECT_UEVENT",
- "nlk_cb_mutex-GENERIC",
- "nlk_cb_mutex-17",
- "nlk_cb_mutex-SCSITRANSPORT",
- "nlk_cb_mutex-ECRYPTFS",
- "nlk_cb_mutex-RDMA",
- "nlk_cb_mutex-CRYPTO",
- "nlk_cb_mutex-SMC",
- "nlk_cb_mutex-23",
- "nlk_cb_mutex-24",
- "nlk_cb_mutex-25",
- "nlk_cb_mutex-26",
- "nlk_cb_mutex-27",
- "nlk_cb_mutex-28",
- "nlk_cb_mutex-29",
- "nlk_cb_mutex-30",
- "nlk_cb_mutex-31",
- "nlk_cb_mutex-MAX_LINKS"
- };
- static int netlink_dump(struct sock *sk);
- /* nl_table locking explained:
- * Lookup and traversal are protected with an RCU read-side lock. Insertion
- * and removal are protected with per bucket lock while using RCU list
- * modification primitives and may run in parallel to RCU protected lookups.
- * Destruction of the Netlink socket may only occur *after* nl_table_lock has
- * been acquired * either during or after the socket has been removed from
- * the list and after an RCU grace period.
- */
- DEFINE_RWLOCK(nl_table_lock);
- EXPORT_SYMBOL_GPL(nl_table_lock);
- static atomic_t nl_table_users = ATOMIC_INIT(0);
- #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));
- static BLOCKING_NOTIFIER_HEAD(netlink_chain);
- static const struct rhashtable_params netlink_rhashtable_params;
- static inline u32 netlink_group_mask(u32 group)
- {
- return group ? 1 << (group - 1) : 0;
- }
- static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
- gfp_t gfp_mask)
- {
- unsigned int len = skb_end_offset(skb);
- struct sk_buff *new;
- new = alloc_skb(len, gfp_mask);
- if (new == NULL)
- return NULL;
- NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
- NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
- NETLINK_CB(new).creds = NETLINK_CB(skb).creds;
- skb_put_data(new, skb->data, len);
- return new;
- }
- static unsigned int netlink_tap_net_id;
- struct netlink_tap_net {
- struct list_head netlink_tap_all;
- struct mutex netlink_tap_lock;
- };
- int netlink_add_tap(struct netlink_tap *nt)
- {
- struct net *net = dev_net(nt->dev);
- struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
- if (unlikely(nt->dev->type != ARPHRD_NETLINK))
- return -EINVAL;
- mutex_lock(&nn->netlink_tap_lock);
- list_add_rcu(&nt->list, &nn->netlink_tap_all);
- mutex_unlock(&nn->netlink_tap_lock);
- __module_get(nt->module);
- return 0;
- }
- EXPORT_SYMBOL_GPL(netlink_add_tap);
- static int __netlink_remove_tap(struct netlink_tap *nt)
- {
- struct net *net = dev_net(nt->dev);
- struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
- bool found = false;
- struct netlink_tap *tmp;
- mutex_lock(&nn->netlink_tap_lock);
- list_for_each_entry(tmp, &nn->netlink_tap_all, list) {
- if (nt == tmp) {
- list_del_rcu(&nt->list);
- found = true;
- goto out;
- }
- }
- pr_warn("__netlink_remove_tap: %p not found\n", nt);
- out:
- mutex_unlock(&nn->netlink_tap_lock);
- if (found)
- module_put(nt->module);
- return found ? 0 : -ENODEV;
- }
- int netlink_remove_tap(struct netlink_tap *nt)
- {
- int ret;
- ret = __netlink_remove_tap(nt);
- synchronize_net();
- return ret;
- }
- EXPORT_SYMBOL_GPL(netlink_remove_tap);
- static __net_init int netlink_tap_init_net(struct net *net)
- {
- struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
- INIT_LIST_HEAD(&nn->netlink_tap_all);
- mutex_init(&nn->netlink_tap_lock);
- return 0;
- }
- static struct pernet_operations netlink_tap_net_ops = {
- .init = netlink_tap_init_net,
- .id = &netlink_tap_net_id,
- .size = sizeof(struct netlink_tap_net),
- };
- static bool netlink_filter_tap(const struct sk_buff *skb)
- {
- struct sock *sk = skb->sk;
- /* We take the more conservative approach and
- * whitelist socket protocols that may pass.
- */
- switch (sk->sk_protocol) {
- case NETLINK_ROUTE:
- case NETLINK_USERSOCK:
- case NETLINK_SOCK_DIAG:
- case NETLINK_NFLOG:
- case NETLINK_XFRM:
- case NETLINK_FIB_LOOKUP:
- case NETLINK_NETFILTER:
- case NETLINK_GENERIC:
- return true;
- }
- return false;
- }
- static int __netlink_deliver_tap_skb(struct sk_buff *skb,
- struct net_device *dev)
- {
- struct sk_buff *nskb;
- struct sock *sk = skb->sk;
- int ret = -ENOMEM;
- if (!net_eq(dev_net(dev), sock_net(sk)))
- return 0;
- dev_hold(dev);
- if (is_vmalloc_addr(skb->head))
- nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
- else
- nskb = skb_clone(skb, GFP_ATOMIC);
- if (nskb) {
- nskb->dev = dev;
- nskb->protocol = htons((u16) sk->sk_protocol);
- nskb->pkt_type = netlink_is_kernel(sk) ?
- PACKET_KERNEL : PACKET_USER;
- skb_reset_network_header(nskb);
- ret = dev_queue_xmit(nskb);
- if (unlikely(ret > 0))
- ret = net_xmit_errno(ret);
- }
- dev_put(dev);
- return ret;
- }
- static void __netlink_deliver_tap(struct sk_buff *skb, struct netlink_tap_net *nn)
- {
- int ret;
- struct netlink_tap *tmp;
- if (!netlink_filter_tap(skb))
- return;
- list_for_each_entry_rcu(tmp, &nn->netlink_tap_all, list) {
- ret = __netlink_deliver_tap_skb(skb, tmp->dev);
- if (unlikely(ret))
- break;
- }
- }
- static void netlink_deliver_tap(struct net *net, struct sk_buff *skb)
- {
- struct netlink_tap_net *nn = net_generic(net, netlink_tap_net_id);
- rcu_read_lock();
- if (unlikely(!list_empty(&nn->netlink_tap_all)))
- __netlink_deliver_tap(skb, nn);
- rcu_read_unlock();
- }
- static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
- struct sk_buff *skb)
- {
- if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
- netlink_deliver_tap(sock_net(dst), skb);
- }
- static void netlink_overrun(struct sock *sk)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
- if (!test_and_set_bit(NETLINK_S_CONGESTED,
- &nlk_sk(sk)->state)) {
- sk->sk_err = ENOBUFS;
- sk->sk_error_report(sk);
- }
- }
- atomic_inc(&sk->sk_drops);
- }
- static void netlink_rcv_wake(struct sock *sk)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- if (skb_queue_empty(&sk->sk_receive_queue))
- clear_bit(NETLINK_S_CONGESTED, &nlk->state);
- if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))
- wake_up_interruptible(&nlk->wait);
- }
- static void netlink_skb_destructor(struct sk_buff *skb)
- {
- if (is_vmalloc_addr(skb->head)) {
- if (!skb->cloned ||
- !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
- vfree(skb->head);
- skb->head = NULL;
- }
- if (skb->sk != NULL)
- sock_rfree(skb);
- }
- static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
- {
- WARN_ON(skb->sk != NULL);
- skb->sk = sk;
- skb->destructor = netlink_skb_destructor;
- atomic_add(skb->truesize, &sk->sk_rmem_alloc);
- sk_mem_charge(sk, skb->truesize);
- }
- static void netlink_sock_destruct(struct sock *sk)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- if (nlk->cb_running) {
- if (nlk->cb.done)
- nlk->cb.done(&nlk->cb);
- module_put(nlk->cb.module);
- kfree_skb(nlk->cb.skb);
- }
- skb_queue_purge(&sk->sk_receive_queue);
- if (!sock_flag(sk, SOCK_DEAD)) {
- printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
- return;
- }
- WARN_ON(atomic_read(&sk->sk_rmem_alloc));
- WARN_ON(refcount_read(&sk->sk_wmem_alloc));
- WARN_ON(nlk_sk(sk)->groups);
- }
- static void netlink_sock_destruct_work(struct work_struct *work)
- {
- struct netlink_sock *nlk = container_of(work, struct netlink_sock,
- work);
- sk_free(&nlk->sk);
- }
- /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
- * SMP. Look, when several writers sleep and reader wakes them up, all but one
- * immediately hit write lock and grab all the cpus. Exclusive sleep solves
- * this, _but_ remember, it adds useless work on UP machines.
- */
- void netlink_table_grab(void)
- __acquires(nl_table_lock)
- {
- might_sleep();
- write_lock_irq(&nl_table_lock);
- if (atomic_read(&nl_table_users)) {
- DECLARE_WAITQUEUE(wait, current);
- add_wait_queue_exclusive(&nl_table_wait, &wait);
- for (;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- if (atomic_read(&nl_table_users) == 0)
- break;
- write_unlock_irq(&nl_table_lock);
- schedule();
- write_lock_irq(&nl_table_lock);
- }
- __set_current_state(TASK_RUNNING);
- remove_wait_queue(&nl_table_wait, &wait);
- }
- }
- void netlink_table_ungrab(void)
- __releases(nl_table_lock)
- {
- write_unlock_irq(&nl_table_lock);
- wake_up(&nl_table_wait);
- }
- static inline void
- netlink_lock_table(void)
- {
- /* read_lock() synchronizes us to netlink_table_grab */
- read_lock(&nl_table_lock);
- atomic_inc(&nl_table_users);
- read_unlock(&nl_table_lock);
- }
- static inline void
- netlink_unlock_table(void)
- {
- if (atomic_dec_and_test(&nl_table_users))
- wake_up(&nl_table_wait);
- }
- struct netlink_compare_arg
- {
- possible_net_t pnet;
- u32 portid;
- };
- /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
- #define netlink_compare_arg_len \
- (offsetof(struct netlink_compare_arg, portid) + sizeof(u32))
- static inline int netlink_compare(struct rhashtable_compare_arg *arg,
- const void *ptr)
- {
- const struct netlink_compare_arg *x = arg->key;
- const struct netlink_sock *nlk = ptr;
- return nlk->portid != x->portid ||
- !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
- }
- static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
- struct net *net, u32 portid)
- {
- memset(arg, 0, sizeof(*arg));
- write_pnet(&arg->pnet, net);
- arg->portid = portid;
- }
- static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
- struct net *net)
- {
- struct netlink_compare_arg arg;
- netlink_compare_arg_init(&arg, net, portid);
- return rhashtable_lookup_fast(&table->hash, &arg,
- netlink_rhashtable_params);
- }
- static int __netlink_insert(struct netlink_table *table, struct sock *sk)
- {
- struct netlink_compare_arg arg;
- netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);
- return rhashtable_lookup_insert_key(&table->hash, &arg,
- &nlk_sk(sk)->node,
- netlink_rhashtable_params);
- }
- static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)
- {
- struct netlink_table *table = &nl_table[protocol];
- struct sock *sk;
- rcu_read_lock();
- sk = __netlink_lookup(table, portid, net);
- if (sk)
- sock_hold(sk);
- rcu_read_unlock();
- return sk;
- }
- static const struct proto_ops netlink_ops;
- static void
- netlink_update_listeners(struct sock *sk)
- {
- struct netlink_table *tbl = &nl_table[sk->sk_protocol];
- unsigned long mask;
- unsigned int i;
- struct listeners *listeners;
- listeners = nl_deref_protected(tbl->listeners);
- if (!listeners)
- return;
- for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {
- mask = 0;
- sk_for_each_bound(sk, &tbl->mc_list) {
- if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
- mask |= nlk_sk(sk)->groups[i];
- }
- listeners->masks[i] = mask;
- }
- /* this function is only called with the netlink table "grabbed", which
- * makes sure updates are visible before bind or setsockopt return. */
- }
- static int netlink_insert(struct sock *sk, u32 portid)
- {
- struct netlink_table *table = &nl_table[sk->sk_protocol];
- int err;
- lock_sock(sk);
- err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
- if (nlk_sk(sk)->bound)
- goto err;
- nlk_sk(sk)->portid = portid;
- sock_hold(sk);
- err = __netlink_insert(table, sk);
- if (err) {
- /* In case the hashtable backend returns with -EBUSY
- * from here, it must not escape to the caller.
- */
- if (unlikely(err == -EBUSY))
- err = -EOVERFLOW;
- if (err == -EEXIST)
- err = -EADDRINUSE;
- sock_put(sk);
- goto err;
- }
- /* We need to ensure that the socket is hashed and visible. */
- smp_wmb();
- nlk_sk(sk)->bound = portid;
- err:
- release_sock(sk);
- return err;
- }
- static void netlink_remove(struct sock *sk)
- {
- struct netlink_table *table;
- table = &nl_table[sk->sk_protocol];
- if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
- netlink_rhashtable_params)) {
- WARN_ON(refcount_read(&sk->sk_refcnt) == 1);
- __sock_put(sk);
- }
- netlink_table_grab();
- if (nlk_sk(sk)->subscriptions) {
- __sk_del_bind_node(sk);
- netlink_update_listeners(sk);
- }
- if (sk->sk_protocol == NETLINK_GENERIC)
- atomic_inc(&genl_sk_destructing_cnt);
- netlink_table_ungrab();
- }
- static struct proto netlink_proto = {
- .name = "NETLINK",
- .owner = THIS_MODULE,
- .obj_size = sizeof(struct netlink_sock),
- };
- static int __netlink_create(struct net *net, struct socket *sock,
- struct mutex *cb_mutex, int protocol,
- int kern)
- {
- struct sock *sk;
- struct netlink_sock *nlk;
- sock->ops = &netlink_ops;
- sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);
- if (!sk)
- return -ENOMEM;
- sock_init_data(sock, sk);
- nlk = nlk_sk(sk);
- if (cb_mutex) {
- nlk->cb_mutex = cb_mutex;
- } else {
- nlk->cb_mutex = &nlk->cb_def_mutex;
- mutex_init(nlk->cb_mutex);
- lockdep_set_class_and_name(nlk->cb_mutex,
- nlk_cb_mutex_keys + protocol,
- nlk_cb_mutex_key_strings[protocol]);
- }
- init_waitqueue_head(&nlk->wait);
- sk->sk_destruct = netlink_sock_destruct;
- sk->sk_protocol = protocol;
- return 0;
- }
- static int netlink_create(struct net *net, struct socket *sock, int protocol,
- int kern)
- {
- struct module *module = NULL;
- struct mutex *cb_mutex;
- struct netlink_sock *nlk;
- int (*bind)(struct net *net, int group);
- void (*unbind)(struct net *net, int group);
- int err = 0;
- sock->state = SS_UNCONNECTED;
- if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
- return -ESOCKTNOSUPPORT;
- if (protocol < 0 || protocol >= MAX_LINKS)
- return -EPROTONOSUPPORT;
- protocol = array_index_nospec(protocol, MAX_LINKS);
- netlink_lock_table();
- #ifdef CONFIG_MODULES
- if (!nl_table[protocol].registered) {
- netlink_unlock_table();
- request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);
- netlink_lock_table();
- }
- #endif
- if (nl_table[protocol].registered &&
- try_module_get(nl_table[protocol].module))
- module = nl_table[protocol].module;
- else
- err = -EPROTONOSUPPORT;
- cb_mutex = nl_table[protocol].cb_mutex;
- bind = nl_table[protocol].bind;
- unbind = nl_table[protocol].unbind;
- netlink_unlock_table();
- if (err < 0)
- goto out;
- err = __netlink_create(net, sock, cb_mutex, protocol, kern);
- if (err < 0)
- goto out_module;
- local_bh_disable();
- sock_prot_inuse_add(net, &netlink_proto, 1);
- local_bh_enable();
- nlk = nlk_sk(sock->sk);
- nlk->module = module;
- nlk->netlink_bind = bind;
- nlk->netlink_unbind = unbind;
- out:
- return err;
- out_module:
- module_put(module);
- goto out;
- }
- static void deferred_put_nlk_sk(struct rcu_head *head)
- {
- struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);
- struct sock *sk = &nlk->sk;
- kfree(nlk->groups);
- nlk->groups = NULL;
- if (!refcount_dec_and_test(&sk->sk_refcnt))
- return;
- if (nlk->cb_running && nlk->cb.done) {
- INIT_WORK(&nlk->work, netlink_sock_destruct_work);
- schedule_work(&nlk->work);
- return;
- }
- sk_free(sk);
- }
- static int netlink_release(struct socket *sock)
- {
- struct sock *sk = sock->sk;
- struct netlink_sock *nlk;
- if (!sk)
- return 0;
- netlink_remove(sk);
- sock_orphan(sk);
- nlk = nlk_sk(sk);
- /*
- * OK. Socket is unlinked, any packets that arrive now
- * will be purged.
- */
- /* must not acquire netlink_table_lock in any way again before unbind
- * and notifying genetlink is done as otherwise it might deadlock
- */
- if (nlk->netlink_unbind) {
- int i;
- for (i = 0; i < nlk->ngroups; i++)
- if (test_bit(i, nlk->groups))
- nlk->netlink_unbind(sock_net(sk), i + 1);
- }
- if (sk->sk_protocol == NETLINK_GENERIC &&
- atomic_dec_return(&genl_sk_destructing_cnt) == 0)
- wake_up(&genl_sk_destructing_waitq);
- sock->sk = NULL;
- wake_up_interruptible_all(&nlk->wait);
- skb_queue_purge(&sk->sk_write_queue);
- if (nlk->portid && nlk->bound) {
- struct netlink_notify n = {
- .net = sock_net(sk),
- .protocol = sk->sk_protocol,
- .portid = nlk->portid,
- };
- blocking_notifier_call_chain(&netlink_chain,
- NETLINK_URELEASE, &n);
- }
- module_put(nlk->module);
- if (netlink_is_kernel(sk)) {
- netlink_table_grab();
- BUG_ON(nl_table[sk->sk_protocol].registered == 0);
- if (--nl_table[sk->sk_protocol].registered == 0) {
- struct listeners *old;
- old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
- RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
- kfree_rcu(old, rcu);
- nl_table[sk->sk_protocol].module = NULL;
- nl_table[sk->sk_protocol].bind = NULL;
- nl_table[sk->sk_protocol].unbind = NULL;
- nl_table[sk->sk_protocol].flags = 0;
- nl_table[sk->sk_protocol].registered = 0;
- }
- netlink_table_ungrab();
- }
- local_bh_disable();
- sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);
- local_bh_enable();
- call_rcu(&nlk->rcu, deferred_put_nlk_sk);
- return 0;
- }
- static int netlink_autobind(struct socket *sock)
- {
- struct sock *sk = sock->sk;
- struct net *net = sock_net(sk);
- struct netlink_table *table = &nl_table[sk->sk_protocol];
- s32 portid = task_tgid_vnr(current);
- int err;
- s32 rover = -4096;
- bool ok;
- retry:
- cond_resched();
- rcu_read_lock();
- ok = !__netlink_lookup(table, portid, net);
- rcu_read_unlock();
- if (!ok) {
- /* Bind collision, search negative portid values. */
- if (rover == -4096)
- /* rover will be in range [S32_MIN, -4097] */
- rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
- else if (rover >= -4096)
- rover = -4097;
- portid = rover--;
- goto retry;
- }
- err = netlink_insert(sk, portid);
- if (err == -EADDRINUSE)
- goto retry;
- /* If 2 threads race to autobind, that is fine. */
- if (err == -EBUSY)
- err = 0;
- return err;
- }
- /**
- * __netlink_ns_capable - General netlink message capability test
- * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
- * @user_ns: The user namespace of the capability to use
- * @cap: The capability to use
- *
- * Test to see if the opener of the socket we received the message
- * from had when the netlink socket was created and the sender of the
- * message has has the capability @cap in the user namespace @user_ns.
- */
- bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
- struct user_namespace *user_ns, int cap)
- {
- return ((nsp->flags & NETLINK_SKB_DST) ||
- file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
- ns_capable(user_ns, cap);
- }
- EXPORT_SYMBOL(__netlink_ns_capable);
- /**
- * netlink_ns_capable - General netlink message capability test
- * @skb: socket buffer holding a netlink command from userspace
- * @user_ns: The user namespace of the capability to use
- * @cap: The capability to use
- *
- * Test to see if the opener of the socket we received the message
- * from had when the netlink socket was created and the sender of the
- * message has has the capability @cap in the user namespace @user_ns.
- */
- bool netlink_ns_capable(const struct sk_buff *skb,
- struct user_namespace *user_ns, int cap)
- {
- return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
- }
- EXPORT_SYMBOL(netlink_ns_capable);
- /**
- * netlink_capable - Netlink global message capability test
- * @skb: socket buffer holding a netlink command from userspace
- * @cap: The capability to use
- *
- * Test to see if the opener of the socket we received the message
- * from had when the netlink socket was created and the sender of the
- * message has has the capability @cap in all user namespaces.
- */
- bool netlink_capable(const struct sk_buff *skb, int cap)
- {
- return netlink_ns_capable(skb, &init_user_ns, cap);
- }
- EXPORT_SYMBOL(netlink_capable);
- /**
- * netlink_net_capable - Netlink network namespace message capability test
- * @skb: socket buffer holding a netlink command from userspace
- * @cap: The capability to use
- *
- * Test to see if the opener of the socket we received the message
- * from had when the netlink socket was created and the sender of the
- * message has has the capability @cap over the network namespace of
- * the socket we received the message from.
- */
- bool netlink_net_capable(const struct sk_buff *skb, int cap)
- {
- return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
- }
- EXPORT_SYMBOL(netlink_net_capable);
- static inline int netlink_allowed(const struct socket *sock, unsigned int flag)
- {
- return (nl_table[sock->sk->sk_protocol].flags & flag) ||
- ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);
- }
- static void
- netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- if (nlk->subscriptions && !subscriptions)
- __sk_del_bind_node(sk);
- else if (!nlk->subscriptions && subscriptions)
- sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
- nlk->subscriptions = subscriptions;
- }
- static int netlink_realloc_groups(struct sock *sk)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- unsigned int groups;
- unsigned long *new_groups;
- int err = 0;
- netlink_table_grab();
- groups = nl_table[sk->sk_protocol].groups;
- if (!nl_table[sk->sk_protocol].registered) {
- err = -ENOENT;
- goto out_unlock;
- }
- if (nlk->ngroups >= groups)
- goto out_unlock;
- new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
- if (new_groups == NULL) {
- err = -ENOMEM;
- goto out_unlock;
- }
- memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,
- NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
- nlk->groups = new_groups;
- nlk->ngroups = groups;
- out_unlock:
- netlink_table_ungrab();
- return err;
- }
- static void netlink_undo_bind(int group, long unsigned int groups,
- struct sock *sk)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- int undo;
- if (!nlk->netlink_unbind)
- return;
- for (undo = 0; undo < group; undo++)
- if (test_bit(undo, &groups))
- nlk->netlink_unbind(sock_net(sk), undo + 1);
- }
- static int netlink_bind(struct socket *sock, struct sockaddr *addr,
- int addr_len)
- {
- struct sock *sk = sock->sk;
- struct net *net = sock_net(sk);
- struct netlink_sock *nlk = nlk_sk(sk);
- struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
- int err = 0;
- unsigned long groups;
- bool bound;
- if (addr_len < sizeof(struct sockaddr_nl))
- return -EINVAL;
- if (nladdr->nl_family != AF_NETLINK)
- return -EINVAL;
- groups = nladdr->nl_groups;
- /* Only superuser is allowed to listen multicasts */
- if (groups) {
- if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
- return -EPERM;
- err = netlink_realloc_groups(sk);
- if (err)
- return err;
- }
- if (nlk->ngroups < BITS_PER_LONG)
- groups &= (1UL << nlk->ngroups) - 1;
- bound = nlk->bound;
- if (bound) {
- /* Ensure nlk->portid is up-to-date. */
- smp_rmb();
- if (nladdr->nl_pid != nlk->portid)
- return -EINVAL;
- }
- netlink_lock_table();
- if (nlk->netlink_bind && groups) {
- int group;
- /* nl_groups is a u32, so cap the maximum groups we can bind */
- for (group = 0; group < BITS_PER_TYPE(u32); group++) {
- if (!test_bit(group, &groups))
- continue;
- err = nlk->netlink_bind(net, group + 1);
- if (!err)
- continue;
- netlink_undo_bind(group, groups, sk);
- goto unlock;
- }
- }
- /* No need for barriers here as we return to user-space without
- * using any of the bound attributes.
- */
- if (!bound) {
- err = nladdr->nl_pid ?
- netlink_insert(sk, nladdr->nl_pid) :
- netlink_autobind(sock);
- if (err) {
- netlink_undo_bind(BITS_PER_TYPE(u32), groups, sk);
- goto unlock;
- }
- }
- if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))
- goto unlock;
- netlink_unlock_table();
- netlink_table_grab();
- netlink_update_subscriptions(sk, nlk->subscriptions +
- hweight32(groups) -
- hweight32(nlk->groups[0]));
- nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;
- netlink_update_listeners(sk);
- netlink_table_ungrab();
- return 0;
- unlock:
- netlink_unlock_table();
- return err;
- }
- static int netlink_connect(struct socket *sock, struct sockaddr *addr,
- int alen, int flags)
- {
- int err = 0;
- struct sock *sk = sock->sk;
- struct netlink_sock *nlk = nlk_sk(sk);
- struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
- if (alen < sizeof(addr->sa_family))
- return -EINVAL;
- if (addr->sa_family == AF_UNSPEC) {
- sk->sk_state = NETLINK_UNCONNECTED;
- nlk->dst_portid = 0;
- nlk->dst_group = 0;
- return 0;
- }
- if (addr->sa_family != AF_NETLINK)
- return -EINVAL;
- if (alen < sizeof(struct sockaddr_nl))
- return -EINVAL;
- if ((nladdr->nl_groups || nladdr->nl_pid) &&
- !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
- return -EPERM;
- /* No need for barriers here as we return to user-space without
- * using any of the bound attributes.
- */
- if (!nlk->bound)
- err = netlink_autobind(sock);
- if (err == 0) {
- sk->sk_state = NETLINK_CONNECTED;
- nlk->dst_portid = nladdr->nl_pid;
- nlk->dst_group = ffs(nladdr->nl_groups);
- }
- return err;
- }
- static int netlink_getname(struct socket *sock, struct sockaddr *addr,
- int peer)
- {
- struct sock *sk = sock->sk;
- struct netlink_sock *nlk = nlk_sk(sk);
- DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);
- nladdr->nl_family = AF_NETLINK;
- nladdr->nl_pad = 0;
- if (peer) {
- nladdr->nl_pid = nlk->dst_portid;
- nladdr->nl_groups = netlink_group_mask(nlk->dst_group);
- } else {
- nladdr->nl_pid = nlk->portid;
- netlink_lock_table();
- nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;
- netlink_unlock_table();
- }
- return sizeof(*nladdr);
- }
- static int netlink_ioctl(struct socket *sock, unsigned int cmd,
- unsigned long arg)
- {
- /* try to hand this ioctl down to the NIC drivers.
- */
- return -ENOIOCTLCMD;
- }
- static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)
- {
- struct sock *sock;
- struct netlink_sock *nlk;
- sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);
- if (!sock)
- return ERR_PTR(-ECONNREFUSED);
- /* Don't bother queuing skb if kernel socket has no input function */
- nlk = nlk_sk(sock);
- if (sock->sk_state == NETLINK_CONNECTED &&
- nlk->dst_portid != nlk_sk(ssk)->portid) {
- sock_put(sock);
- return ERR_PTR(-ECONNREFUSED);
- }
- return sock;
- }
- struct sock *netlink_getsockbyfilp(struct file *filp)
- {
- struct inode *inode = file_inode(filp);
- struct sock *sock;
- if (!S_ISSOCK(inode->i_mode))
- return ERR_PTR(-ENOTSOCK);
- sock = SOCKET_I(inode)->sk;
- if (sock->sk_family != AF_NETLINK)
- return ERR_PTR(-EINVAL);
- sock_hold(sock);
- return sock;
- }
- static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
- int broadcast)
- {
- struct sk_buff *skb;
- void *data;
- if (size <= NLMSG_GOODSIZE || broadcast)
- return alloc_skb(size, GFP_KERNEL);
- size = SKB_DATA_ALIGN(size) +
- SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
- data = vmalloc(size);
- if (data == NULL)
- return NULL;
- skb = __build_skb(data, size);
- if (skb == NULL)
- vfree(data);
- else
- skb->destructor = netlink_skb_destructor;
- return skb;
- }
- /*
- * Attach a skb to a netlink socket.
- * The caller must hold a reference to the destination socket. On error, the
- * reference is dropped. The skb is not send to the destination, just all
- * all error checks are performed and memory in the queue is reserved.
- * Return values:
- * < 0: error. skb freed, reference to sock dropped.
- * 0: continue
- * 1: repeat lookup - reference dropped while waiting for socket memory.
- */
- int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
- long *timeo, struct sock *ssk)
- {
- struct netlink_sock *nlk;
- nlk = nlk_sk(sk);
- if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
- test_bit(NETLINK_S_CONGESTED, &nlk->state))) {
- DECLARE_WAITQUEUE(wait, current);
- if (!*timeo) {
- if (!ssk || netlink_is_kernel(ssk))
- netlink_overrun(sk);
- sock_put(sk);
- kfree_skb(skb);
- return -EAGAIN;
- }
- __set_current_state(TASK_INTERRUPTIBLE);
- add_wait_queue(&nlk->wait, &wait);
- if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||
- test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&
- !sock_flag(sk, SOCK_DEAD))
- *timeo = schedule_timeout(*timeo);
- __set_current_state(TASK_RUNNING);
- remove_wait_queue(&nlk->wait, &wait);
- sock_put(sk);
- if (signal_pending(current)) {
- kfree_skb(skb);
- return sock_intr_errno(*timeo);
- }
- return 1;
- }
- netlink_skb_set_owner_r(skb, sk);
- return 0;
- }
- static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
- {
- int len = skb->len;
- netlink_deliver_tap(sock_net(sk), skb);
- skb_queue_tail(&sk->sk_receive_queue, skb);
- sk->sk_data_ready(sk);
- return len;
- }
- int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
- {
- int len = __netlink_sendskb(sk, skb);
- sock_put(sk);
- return len;
- }
- void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
- {
- kfree_skb(skb);
- sock_put(sk);
- }
- static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)
- {
- int delta;
- WARN_ON(skb->sk != NULL);
- delta = skb->end - skb->tail;
- if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)
- return skb;
- if (skb_shared(skb)) {
- struct sk_buff *nskb = skb_clone(skb, allocation);
- if (!nskb)
- return skb;
- consume_skb(skb);
- skb = nskb;
- }
- pskb_expand_head(skb, 0, -delta,
- (allocation & ~__GFP_DIRECT_RECLAIM) |
- __GFP_NOWARN | __GFP_NORETRY);
- return skb;
- }
- static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
- struct sock *ssk)
- {
- int ret;
- struct netlink_sock *nlk = nlk_sk(sk);
- ret = -ECONNREFUSED;
- if (nlk->netlink_rcv != NULL) {
- ret = skb->len;
- netlink_skb_set_owner_r(skb, sk);
- NETLINK_CB(skb).sk = ssk;
- netlink_deliver_tap_kernel(sk, ssk, skb);
- nlk->netlink_rcv(skb);
- consume_skb(skb);
- } else {
- kfree_skb(skb);
- }
- sock_put(sk);
- return ret;
- }
- int netlink_unicast(struct sock *ssk, struct sk_buff *skb,
- u32 portid, int nonblock)
- {
- struct sock *sk;
- int err;
- long timeo;
- skb = netlink_trim(skb, gfp_any());
- timeo = sock_sndtimeo(ssk, nonblock);
- retry:
- sk = netlink_getsockbyportid(ssk, portid);
- if (IS_ERR(sk)) {
- kfree_skb(skb);
- return PTR_ERR(sk);
- }
- if (netlink_is_kernel(sk))
- return netlink_unicast_kernel(sk, skb, ssk);
- if (sk_filter(sk, skb)) {
- err = skb->len;
- kfree_skb(skb);
- sock_put(sk);
- return err;
- }
- err = netlink_attachskb(sk, skb, &timeo, ssk);
- if (err == 1)
- goto retry;
- if (err)
- return err;
- return netlink_sendskb(sk, skb);
- }
- EXPORT_SYMBOL(netlink_unicast);
- int netlink_has_listeners(struct sock *sk, unsigned int group)
- {
- int res = 0;
- struct listeners *listeners;
- BUG_ON(!netlink_is_kernel(sk));
- rcu_read_lock();
- listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);
- if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)
- res = test_bit(group - 1, listeners->masks);
- rcu_read_unlock();
- return res;
- }
- EXPORT_SYMBOL_GPL(netlink_has_listeners);
- bool netlink_strict_get_check(struct sk_buff *skb)
- {
- const struct netlink_sock *nlk = nlk_sk(NETLINK_CB(skb).sk);
- return nlk->flags & NETLINK_F_STRICT_CHK;
- }
- EXPORT_SYMBOL_GPL(netlink_strict_get_check);
- static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
- !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {
- netlink_skb_set_owner_r(skb, sk);
- __netlink_sendskb(sk, skb);
- return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);
- }
- return -1;
- }
- struct netlink_broadcast_data {
- struct sock *exclude_sk;
- struct net *net;
- u32 portid;
- u32 group;
- int failure;
- int delivery_failure;
- int congested;
- int delivered;
- gfp_t allocation;
- struct sk_buff *skb, *skb2;
- int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
- void *tx_data;
- };
- static void do_one_broadcast(struct sock *sk,
- struct netlink_broadcast_data *p)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- int val;
- if (p->exclude_sk == sk)
- return;
- if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
- !test_bit(p->group - 1, nlk->groups))
- return;
- if (!net_eq(sock_net(sk), p->net)) {
- if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
- return;
- if (!peernet_has_id(sock_net(sk), p->net))
- return;
- if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
- CAP_NET_BROADCAST))
- return;
- }
- if (p->failure) {
- netlink_overrun(sk);
- return;
- }
- sock_hold(sk);
- if (p->skb2 == NULL) {
- if (skb_shared(p->skb)) {
- p->skb2 = skb_clone(p->skb, p->allocation);
- } else {
- p->skb2 = skb_get(p->skb);
- /*
- * skb ownership may have been set when
- * delivered to a previous socket.
- */
- skb_orphan(p->skb2);
- }
- }
- if (p->skb2 == NULL) {
- netlink_overrun(sk);
- /* Clone failed. Notify ALL listeners. */
- p->failure = 1;
- if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
- p->delivery_failure = 1;
- goto out;
- }
- if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {
- kfree_skb(p->skb2);
- p->skb2 = NULL;
- goto out;
- }
- if (sk_filter(sk, p->skb2)) {
- kfree_skb(p->skb2);
- p->skb2 = NULL;
- goto out;
- }
- NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);
- if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
- NETLINK_CB(p->skb2).nsid_is_set = true;
- val = netlink_broadcast_deliver(sk, p->skb2);
- if (val < 0) {
- netlink_overrun(sk);
- if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)
- p->delivery_failure = 1;
- } else {
- p->congested |= val;
- p->delivered = 1;
- p->skb2 = NULL;
- }
- out:
- sock_put(sk);
- }
- int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,
- u32 group, gfp_t allocation,
- int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
- void *filter_data)
- {
- struct net *net = sock_net(ssk);
- struct netlink_broadcast_data info;
- struct sock *sk;
- skb = netlink_trim(skb, allocation);
- info.exclude_sk = ssk;
- info.net = net;
- info.portid = portid;
- info.group = group;
- info.failure = 0;
- info.delivery_failure = 0;
- info.congested = 0;
- info.delivered = 0;
- info.allocation = allocation;
- info.skb = skb;
- info.skb2 = NULL;
- info.tx_filter = filter;
- info.tx_data = filter_data;
- /* While we sleep in clone, do not allow to change socket list */
- netlink_lock_table();
- sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
- do_one_broadcast(sk, &info);
- consume_skb(skb);
- netlink_unlock_table();
- if (info.delivery_failure) {
- kfree_skb(info.skb2);
- return -ENOBUFS;
- }
- consume_skb(info.skb2);
- if (info.delivered) {
- if (info.congested && gfpflags_allow_blocking(allocation))
- yield();
- return 0;
- }
- return -ESRCH;
- }
- EXPORT_SYMBOL(netlink_broadcast_filtered);
- int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,
- u32 group, gfp_t allocation)
- {
- return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,
- NULL, NULL);
- }
- EXPORT_SYMBOL(netlink_broadcast);
- struct netlink_set_err_data {
- struct sock *exclude_sk;
- u32 portid;
- u32 group;
- int code;
- };
- static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)
- {
- struct netlink_sock *nlk = nlk_sk(sk);
- int ret = 0;
- if (sk == p->exclude_sk)
- goto out;
- if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))
- goto out;
- if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||
- !test_bit(p->group - 1, nlk->groups))
- goto out;
- if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {
- ret = 1;
- goto out;
- }
- sk->sk_err = p->code;
- sk->sk_error_report(sk);
- out:
- return ret;
- }
- /**
- * netlink_set_err - report error to broadcast listeners
- * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()
- * @portid: the PORTID of a process that we want to skip (if any)
- * @group: the broadcast group that will notice the error
- * @code: error code, must be negative (as usual in kernelspace)
- *
- * This function returns the number of broadcast listeners that have set the
- * NETLINK_NO_ENOBUFS socket option.
- */
- int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)
- {
- struct netlink_set_err_data info;
- struct sock *sk;
- int ret = 0;
- info.exclude_sk = ssk;
- info.portid = portid;
- info.group = group;
- /* sk->sk_err wants a positive error value */
- info.code = -code;
- read_lock(&nl_table_lock);
- sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
- ret += do_one_set_err(sk, &info);
- read_unlock(&nl_table_lock);
- return ret;
- }
- EXPORT_SYMBOL(netlink_set_err);
- /* must be called with netlink table grabbed */
- static void netlink_update_socket_mc(struct netlink_sock *nlk,
- unsigned int group,
- int is_new)
- {
- int old, new = !!is_new, subscriptions;
- old = test_bit(group - 1, nlk->groups);
- subscriptions = nlk->subscriptions - old + new;
- if (new)
- __set_bit(group - 1, nlk->groups);
- else
- __clear_bit(group - 1, nlk->groups);
- netlink_update_subscriptions(&nlk->sk, subscriptions);
- netlink_update_listeners(&nlk->sk);
- }
- static int netlink_setsockopt(struct socket *sock, int level, int optname,
- char __user *optval, unsigned int optlen)
- {
- struct sock *sk = sock->sk;
- struct netlink_sock *nlk = nlk_sk(sk);
- unsigned int val = 0;
- int err;
- if (level != SOL_NETLINK)
- return -ENOPROTOOPT;
- if (optlen >= sizeof(int) &&
- get_user(val, (unsigned int __user *)optval))
- return -EFAULT;
- switch (optname) {
- case NETLINK_PKTINFO:
- if (val)
- nlk->flags |= NETLINK_F_RECV_PKTINFO;
- else
- nlk->flags &= ~NETLINK_F_RECV_PKTINFO;
- err = 0;
- break;
- case NETLINK_ADD_MEMBERSHIP:
- case NETLINK_DROP_MEMBERSHIP: {
- if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))
- return -EPERM;
- err = netlink_realloc_groups(sk);
- if (err)
- return err;
- if (!val || val - 1 >= nlk->ngroups)
- return -EINVAL;
- if (optname == NETLINK_ADD_MEMBERSHIP && nlk->netlink_bind) {
- err = nlk->netlink_bind(sock_net(sk), val);
- if (err)
- return err;
- }
- netlink_table_grab();
- netlink_update_socket_mc(nlk, val,
- optname == NETLINK_ADD_MEMBERSHIP);
- netlink_table_ungrab();
- if (optname == NETLINK_DROP_MEMBERSHIP && nlk->netlink_unbind)
- nlk->netlink_unbind(sock_net(sk), val);
- err = 0;
- break;
- }
- case NETLINK_BROADCAST_ERROR:
- if (val)
- nlk->flags |= NETLINK_F_BROADCAST_SEND_ERROR;
- else
- nlk->flags &= ~NETLINK_F_BROADCAST_SEND_ERROR;
- err = 0;
- break;
- case NETLINK_NO_ENOBUFS:
- if (val) {
- nlk->flags |= NETLINK_F_RECV_NO_ENOBUFS;
- clear_bit(NETLINK_S_CONGESTED, &nlk->state);
- wake_up_interruptible(&nlk->wait);
- } else {
- nlk->flags &= ~NETLINK_F_RECV_NO_ENOBUFS;
- }
- err = 0;
- break;
- case NETLINK_LISTEN_ALL_NSID:
- if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST))
- return -EPERM;
- if (val)
- nlk->flags |= NETLINK_F_LISTEN_ALL_NSID;
- else
- nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
- err = 0;
- break;
- case NETLINK_CAP_ACK:
- if (val)
- nlk->flags |= NETLINK_F_CAP_ACK;
- else
- nlk->flags &= ~NETLINK_F_CAP_ACK;
- err = 0;
- break;
- case NETLINK_EXT_ACK:
- if (val)
- nlk->flags |= NETLINK_F_EXT_ACK;
- else
- nlk->flags &= ~NETLINK_F_EXT_ACK;
- err = 0;
- break;
- case NETLINK_GET_STRICT_CHK:
- if (val)
- nlk->flags |= NETLINK_F_STRICT_CHK;
- else
- nlk->flags &= ~NETLINK_F_STRICT_CHK;
- err = 0;
- break;
- default:
- err = -ENOPROTOOPT;
- }
- return err;
- }
- static int netlink_getsockopt(struct socket *sock, int level, int optname,
- char __user *optval, int __user *optlen)
- {
- struct sock *sk = sock->sk;
- struct netlink_sock *nlk = nlk_sk(sk);
- int len, val, err;
- if (level != SOL_NETLINK)
- return -ENOPROTOOPT;
- if (get_user(len, optlen))
- return -EFAULT;
- if (len < 0)
- return -EINVAL;
- switch (optname) {
- case NETLINK_PKTINFO:
- if (len < sizeof(int))
- return -EINVAL;
- len = sizeof(int);
- val = nlk->flags & NETLINK_F_RECV_PKTINFO ? 1 : 0;
- if (put_user(len, optlen) ||
- put_user(val, optval))
- return -EFAULT;
- err = 0;
- break;
- case NETLINK_BROADCAST_ERROR:
- if (len < sizeof(int))
- return -EINVAL;
- len = sizeof(int);
- val = nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR ? 1 : 0;
- if (put_user(len, optlen) ||
- put_user(val, optval))
- return -EFAULT;
- err = 0;
- break;
- case NETLINK_NO_ENOBUFS:
- if (len < sizeof(int))
- return -EINVAL;
- len = sizeof(int);
- val = nlk->flags & NETLINK_F_RECV_NO_ENOBUFS ? 1 : 0;
- if (put_user(len, optlen) ||
- put_user(val, optval))
- return -EFAULT;
- err = 0;
- break;
- case NETLINK_LIST_MEMBERSHIPS: {
- int pos, idx, shift;
- err = 0;
- netlink_lock_table();
- for (pos = 0; pos * 8 < nlk->ngroups; pos += sizeof(u32)) {
- if (len - pos < sizeof(u32))
- break;
- idx = pos / sizeof(unsigned long);
- shift = (pos % sizeof(unsigned long)) * 8;
- if (put_user((u32)(nlk->groups[idx] >> shift),
- (u32 __user *)(optval + pos))) {
- err = -EFAULT;
- break;
- }
- }
- if (put_user(ALIGN(nlk->ngroups / 8, sizeof(u32)), optlen))
- err = -EFAULT;
- netlink_unlock_table();
- break;
- }
- case NETLINK_CAP_ACK:
- if (len < sizeof(int))
- return -EINVAL;
- len = sizeof(int);
- val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
- if (put_user(len, optlen) ||
- put_user(val, optval))
- return -EFAULT;
- err = 0;
- break;
- case NETLINK_EXT_ACK:
- if (len < sizeof(int))
- return -EINVAL;
- len = sizeof(int);
- val = nlk->flags & NETLINK_F_EXT_ACK ? 1 : 0;
- if (put_user(len, optlen) || put_user(val, optval))
- return -EFAULT;
- err = 0;
- break;
- case NETLINK_GET_STRICT_CHK:
- if (len < sizeof(int))
- return -EINVAL;
- len = sizeof(int);
- val = nlk->flags & NETLINK_F_STRICT_CHK ? 1 : 0;
- if (put_user(len, optlen) || put_user(val, optval))
- return -EFAULT;
- err = 0;
- break;
- default:
- err = -ENOPROTOOPT;
- }
- return err;
- }
- static void netlink_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
- {
- struct nl_pktinfo info;
- info.group = NETLINK_CB(skb).dst_group;
- put_cmsg(msg, SOL_NETLINK, NETLINK_PKTINFO, sizeof(info), &info);
- }
- static void netlink_cmsg_listen_all_nsid(struct sock *sk, struct msghdr *msg,
- struct sk_buff *skb)
- {
- if (!NETLINK_CB(skb).nsid_is_set)
- return;
- put_cmsg(msg, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, sizeof(int),
- &NETLINK_CB(skb).nsid);
- }
- static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
- {
- struct sock *sk = sock->sk;
- struct netlink_sock *nlk = nlk_sk(sk);
- DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
- u32 dst_portid;
- u32 dst_group;
- struct sk_buff *skb;
- int err;
- struct scm_cookie scm;
- u32 netlink_skb_flags = 0;
- if (msg->msg_flags&MSG_OOB)
- return -EOPNOTSUPP;
- err = scm_send(sock, msg, &scm, true);
- if (err < 0)
- return err;
- if (msg->msg_namelen) {
- err = -EINVAL;
- if (msg->msg_namelen < sizeof(struct sockaddr_nl))
- goto out;
- if (addr->nl_family != AF_NETLINK)
- goto out;
- dst_portid = addr->nl_pid;
- dst_group = ffs(addr->nl_groups);
- err = -EPERM;
- if ((dst_group || dst_portid) &&
- !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))
- goto out;
- netlink_skb_flags |= NETLINK_SKB_DST;
- } else {
- dst_portid = nlk->dst_portid;
- dst_group = nlk->dst_group;
- }
- if (!nlk->bound) {
- err = netlink_autobind(sock);
- if (err)
- goto out;
- } else {
- /* Ensure nlk is hashed and visible. */
- smp_rmb();
- }
- err = -EMSGSIZE;
- if (len > sk->sk_sndbuf - 32)
- goto out;
- err = -ENOBUFS;
- skb = netlink_alloc_large_skb(len, dst_group);
- if (skb == NULL)
- goto out;
- NETLINK_CB(skb).portid = nlk->portid;
- NETLINK_CB(skb).dst_group = dst_group;
- NETLINK_CB(skb).creds = scm.creds;
- NETLINK_CB(skb).flags = netlink_skb_flags;
- err = -EFAULT;
- if (memcpy_from_msg(skb_put(skb, len), msg, len)) {
- kfree_skb(skb);
- goto out;
- }
- err = security_netlink_send(sk, skb);
- if (err) {
- kfree_skb(skb);
- goto out;
- }
- if (dst_group) {
- refcount_inc(&skb->users);
- netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL);
- }
- err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags&MSG_DONTWAIT);
- out:
- scm_destroy(&scm);
- return err;
- }
- static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
- int flags)
- {
- struct scm_cookie scm;
- struct sock *sk = sock->sk;
- struct netlink_sock *nlk = nlk_sk(sk);
- int noblock = flags&MSG_DONTWAIT;
- size_t copied;
- struct sk_buff *skb, *data_skb;
- int err, ret;
- if (flags&MSG_OOB)
- return -EOPNOTSUPP;
- copied = 0;
- skb = skb_recv_datagram(sk, flags, noblock, &err);
- if (skb == NULL)
- goto out;
- data_skb = skb;
- #ifdef CONFIG_COMPAT_NETLINK_MESSAGES
- if (unlikely(skb_shinfo(skb)->frag_list)) {
- /*
- * If this skb has a frag_list, then here that means that we
- * will have to use the frag_list skb's data for compat tasks
- * and the regular skb's data for normal (non-compat) tasks.
- *
- * If we need to send the compat skb, assign it to the
- * 'data_skb' variable so that it will be used below for data
- * copying. We keep 'skb' for everything else, including
- * freeing both later.
- */
- if (flags & MSG_CMSG_COMPAT)
- data_skb = skb_shinfo(skb)->frag_list;
- }
- #endif
- /* Record the max length of recvmsg() calls for future allocations */
- nlk->max_recvmsg_len = max(nlk->max_recvmsg_len, len);
- nlk->max_recvmsg_len = min_t(size_t, nlk->max_recvmsg_len,
- SKB_WITH_OVERHEAD(32768));
- copied = data_skb->len;
- if (len < copied) {
- msg->msg_flags |= MSG_TRUNC;
- copied = len;
- }
- skb_reset_transport_header(data_skb);
- err = skb_copy_datagram_msg(data_skb, 0, msg, copied);
- if (msg->msg_name) {
- DECLARE_SOCKADDR(struct sockaddr_nl *, addr, msg->msg_name);
- addr->nl_family = AF_NETLINK;
- addr->nl_pad = 0;
- addr->nl_pid = NETLINK_CB(skb).portid;
- addr->nl_groups = netlink_group_mask(NETLINK_CB(skb).dst_group);
- msg->msg_namelen = sizeof(*addr);
- }
- if (nlk->flags & NETLINK_F_RECV_PKTINFO)
- netlink_cmsg_recv_pktinfo(msg, skb);
- if (nlk->flags & NETLINK_F_LISTEN_ALL_NSID)
- netlink_cmsg_listen_all_nsid(sk, msg, skb);
- memset(&scm, 0, sizeof(scm));
- scm.creds = *NETLINK_CREDS(skb);
- if (flags & MSG_TRUNC)
- copied = data_skb->len;
- skb_free_datagram(sk, skb);
- if (nlk->cb_running &&
- atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) {
- ret = netlink_dump(sk);
- if (ret) {
- sk->sk_err = -ret;
- sk->sk_error_report(sk);
- }
- }
- scm_recv(sock, msg, &scm, flags);
- out:
- netlink_rcv_wake(sk);
- return err ? : copied;
- }
- static void netlink_data_ready(struct sock *sk)
- {
- BUG();
- }
- /*
- * We export these functions to other modules. They provide a
- * complete set of kernel non-blocking support for message
- * queueing.
- */
- struct sock *
- __netlink_kernel_create(struct net *net, int unit, struct module *module,
- struct netlink_kernel_cfg *cfg)
- {
- struct socket *sock;
- struct sock *sk;
- struct netlink_sock *nlk;
- struct listeners *listeners = NULL;
- struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
- unsigned int groups;
- BUG_ON(!nl_table);
- if (unit < 0 || unit >= MAX_LINKS)
- return NULL;
- if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
- return NULL;
- if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
- goto out_sock_release_nosk;
- sk = sock->sk;
- if (!cfg || cfg->groups < 32)
- groups = 32;
- else
- groups = cfg->groups;
- listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL);
- if (!listeners)
- goto out_sock_release;
- sk->sk_data_ready = netlink_data_ready;
- if (cfg && cfg->input)
- nlk_sk(sk)->netlink_rcv = cfg->input;
- if (netlink_insert(sk, 0))
- goto out_sock_release;
- nlk = nlk_sk(sk);
- nlk->flags |= NETLINK_F_KERNEL_SOCKET;
- netlink_table_grab();
- if (!nl_table[unit].registered) {
- nl_table[unit].groups = groups;
- rcu_assign_pointer(nl_table[unit].listeners, listeners);
- nl_table[unit].cb_mutex = cb_mutex;
- nl_table[unit].module = module;
- if (cfg) {
- nl_table[unit].bind = cfg->bind;
- nl_table[unit].unbind = cfg->unbind;
- nl_table[unit].flags = cfg->flags;
- if (cfg->compare)
- nl_table[unit].compare = cfg->compare;
- }
- nl_table[unit].registered = 1;
- } else {
- kfree(listeners);
- nl_table[unit].registered++;
- }
- netlink_table_ungrab();
- return sk;
- out_sock_release:
- kfree(listeners);
- netlink_kernel_release(sk);
- return NULL;
- out_sock_release_nosk:
- sock_release(…