diff options
Diffstat (limited to 'net/netlink/af_netlink.c')
| -rw-r--r-- | net/netlink/af_netlink.c | 2953 |
1 files changed, 2953 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c new file mode 100644 index 000000000..d9107b545 --- /dev/null +++ b/net/netlink/af_netlink.c @@ -0,0 +1,2953 @@ +// 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/bpf.h> +#include <linux/capability.h> +#include <linux/kernel.h> +#include <linux/filter.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 <linux/btf_ids.h> + +#include <net/net_namespace.h> +#include <net/netns/generic.h> +#include <net/sock.h> +#include <net/scm.h> +#include <net/netlink.h> +#define CREATE_TRACE_POINTS +#include <trace/events/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_test_bit(KERNEL_SOCKET, sk); +} + +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; + +void do_trace_netlink_extack(const char *msg) +{ + trace_netlink_extack(msg); +} +EXPORT_SYMBOL(do_trace_netlink_extack); + +static inline u32 netlink_group_mask(u32 group) +{ + if (group > 32) + return 0; + 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) +{ + if (!nlk_test_bit(RECV_NO_ENOBUFS, sk)) { + if (!test_and_set_bit(NETLINK_S_CONGESTED, + &nlk_sk(sk)->state)) { + WRITE_ONCE(sk->sk_err, ENOBUFS); + 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_lockless(&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_atomic(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) +{ + unsigned long flags; + + /* read_lock() synchronizes us to netlink_table_grab */ + + read_lock_irqsave(&nl_table_lock, flags); + atomic_inc(&nl_table_users); + read_unlock_irqrestore(&nl_table_lock, flags); +} + +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; + + /* portid can be read locklessly from netlink_getname(). */ + WRITE_ONCE(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(); + /* Paired with lockless reads from netlink_bind(), + * netlink_connect() and netlink_sendmsg(). + */ + WRITE_ONCE(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); + void (*release)(struct sock *sock, unsigned long *groups); + 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; + release = nl_table[protocol].release; + netlink_unlock_table(); + + if (err < 0) + goto out; + + err = __netlink_create(net, sock, cb_mutex, protocol, kern); + if (err < 0) + goto out_module; + + sock_prot_inuse_add(net, &netlink_proto, 1); + + nlk = nlk_sk(sock->sk); + nlk->module = module; + nlk->netlink_bind = bind; + nlk->netlink_unbind = unbind; + nlk->netlink_release = release; +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. + */ + if (nlk->netlink_release) + nlk->netlink_release(sk, nlk->groups); + + /* 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(); + } + + sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1); + + /* Because struct net might disappear soon, do not keep a pointer. */ + if (!sk->sk_net_refcnt && sock_net(sk) != &init_net) { + __netns_tracker_free(sock_net(sk), &sk->ns_tracker, false); + /* Because of deferred_put_nlk_sk and use of work queue, + * it is possible netns will be freed before this socket. + */ + sock_net_set(sk, &init_net); + __netns_tracker_alloc(&init_net, &sk->ns_tracker, + false, GFP_KERNEL); + } + 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 + get_random_u32_below(-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 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 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 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 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; + + /* Paired with WRITE_ONCE() in netlink_insert() */ + bound = READ_ONCE(nlk->bound); + if (bound) { + /* Ensure nlk->portid is up-to-date. */ + smp_rmb(); + + if (nladdr->nl_pid != nlk->portid) + return -EINVAL; + } + + 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); + return err; + } + } + + /* No need for barriers here as we return to user-space without + * using any of the bound attributes. + */ + netlink_lock_table(); + 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) { + /* paired with READ_ONCE() in netlink_getsockbyportid() */ + WRITE_ONCE(sk->sk_state, NETLINK_UNCONNECTED); + /* dst_portid and dst_group can be read locklessly */ + WRITE_ONCE(nlk->dst_portid, 0); + WRITE_ONCE(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. + * Paired with WRITE_ONCE() in netlink_insert(). + */ + if (!READ_ONCE(nlk->bound)) + err = netlink_autobind(sock); + + if (err == 0) { + /* paired with READ_ONCE() in netlink_getsockbyportid() */ + WRITE_ONCE(sk->sk_state, NETLINK_CONNECTED); + /* dst_portid and dst_group can be read locklessly */ + WRITE_ONCE(nlk->dst_portid, nladdr->nl_pid); + WRITE_ONCE(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) { + /* Paired with WRITE_ONCE() in netlink_connect() */ + nladdr->nl_pid = READ_ONCE(nlk->dst_portid); + nladdr->nl_groups = netlink_group_mask(READ_ONCE(nlk->dst_group)); + } else { + /* Paired with WRITE_ONCE() in netlink_insert() */ + nladdr->nl_pid = READ_ONCE(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); + /* dst_portid and sk_state can be changed in netlink_connect() */ + if (READ_ONCE(sock->sk_state) == NETLINK_CONNECTED && + READ_ONCE(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) +{ + return nlk_test_bit(STRICT_CHK, NETLINK_CB(skb).sk); +} +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_test_bit(LISTEN_ALL_NSID, sk)) + 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_test_bit(BROADCAST_SEND_ERROR, sk)) + 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_test_bit(BROADCAST_SEND_ERROR, sk)) + 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_test_bit(RECV_NO_ENOBUFS, sk)) { + ret = 1; + goto out; + } + + WRITE_ONCE(sk->sk_err, p->code); + 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; + unsigned long flags; + 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_irqsave(&nl_table_lock, flags); + + sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list) + ret += do_one_set_err(sk, &info); + + read_unlock_irqrestore(&nl_table_lock, flags); + 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; + __assign_bit(group - 1, nlk->groups, new); + netlink_update_subscriptions(&nlk->sk, subscriptions); + netlink_update_listeners(&nlk->sk); +} + +static int netlink_setsockopt(struct socket *sock, int level, int optname, + sockptr_t optval, unsigned int optlen) +{ + struct sock *sk = sock->sk; + struct netlink_sock *nlk = nlk_sk(sk); + unsigned int val = 0; + int nr = -1; + + if (level != SOL_NETLINK) + return -ENOPROTOOPT; + + if (optlen >= sizeof(int) && + copy_from_sockptr(&val, optval, sizeof(val))) + return -EFAULT; + + switch (optname) { + case NETLINK_PKTINFO: + nr = NETLINK_F_RECV_PKTINFO; + break; + case NETLINK_ADD_MEMBERSHIP: + case NETLINK_DROP_MEMBERSHIP: { + int err; + + 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); + + break; + } + case NETLINK_BROADCAST_ERROR: + nr = NETLINK_F_BROADCAST_SEND_ERROR; + break; + case NETLINK_NO_ENOBUFS: + assign_bit(NETLINK_F_RECV_NO_ENOBUFS, &nlk->flags, val); + if (val) { + clear_bit(NETLINK_S_CONGESTED, &nlk->state); + wake_up_interruptible(&nlk->wait); + } + break; + case NETLINK_LISTEN_ALL_NSID: + if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_BROADCAST)) + return -EPERM; + nr = NETLINK_F_LISTEN_ALL_NSID; + break; + case NETLINK_CAP_ACK: + nr = NETLINK_F_CAP_ACK; + break; + case NETLINK_EXT_ACK: + nr = NETLINK_F_EXT_ACK; + break; + case NETLINK_GET_STRICT_CHK: + nr = NETLINK_F_STRICT_CHK; + break; + default: + return -ENOPROTOOPT; + } + if (nr >= 0) + assign_bit(nr, &nlk->flags, val); + return 0; +} + +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); + unsigned int flag; + int len, val; + + if (level != SOL_NETLINK) + return -ENOPROTOOPT; + + if (get_user(len, optlen)) + return -EFAULT; + if (len < 0) + return -EINVAL; + + switch (optname) { + case NETLINK_PKTINFO: + flag = NETLINK_F_RECV_PKTINFO; + break; + case NETLINK_BROADCAST_ERROR: + flag = NETLINK_F_BROADCAST_SEND_ERROR; + break; + case NETLINK_NO_ENOBUFS: + flag = NETLINK_F_RECV_NO_ENOBUFS; + 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(BITS_TO_BYTES(nlk->ngroups), sizeof(u32)), optlen)) + err = -EFAULT; + netlink_unlock_table(); + return err; + } + case NETLINK_CAP_ACK: + flag = NETLINK_F_CAP_ACK; + break; + case NETLINK_EXT_ACK: + flag = NETLINK_F_EXT_ACK; + break; + case NETLINK_GET_STRICT_CHK: + flag = NETLINK_F_STRICT_CHK; + break; + default: + return -ENOPROTOOPT; + } + + if (len < sizeof(int)) + return -EINVAL; + + len = sizeof(int); + val = test_bit(flag, &nlk->flags); + + if (put_user(len, optlen) || + copy_to_user(optval, &val, len)) + return -EFAULT; + + return 0; +} + +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; + + if (len == 0) { + pr_warn_once("Zero length message leads to an empty skb\n"); + return -ENODATA; + } + + 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 { + /* Paired with WRITE_ONCE() in netlink_connect() */ + dst_portid = READ_ONCE(nlk->dst_portid); + dst_group = READ_ONCE(nlk->dst_group); + } + + /* Paired with WRITE_ONCE() in netlink_insert() */ + if (!READ_ONCE(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); + size_t copied, max_recvmsg_len; + struct sk_buff *skb, *data_skb; + int err, ret; + + if (flags & MSG_OOB) + return -EOPNOTSUPP; + + copied = 0; + + skb = skb_recv_datagram(sk, flags, &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 */ + max_recvmsg_len = max(READ_ONCE(nlk->max_recvmsg_len), len); + max_recvmsg_len = min_t(size_t, max_recvmsg_len, + SKB_WITH_OVERHEAD(32768)); + WRITE_ONCE(nlk->max_recvmsg_len, max_recvmsg_len); + + copied = data_skb->len; + if (len < copied) { + msg->msg_flags |= MSG_TRUNC; + copied = len; + } + + 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_test_bit(RECV_PKTINFO, sk)) + netlink_cmsg_recv_pktinfo(msg, skb); + if (nlk_test_bit(LISTEN_ALL_NSID, sk)) + 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 (READ_ONCE(nlk->cb_running) && + atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { + ret = netlink_dump(sk); + if (ret) { + WRITE_ONCE(sk->sk_err, -ret); + 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); + set_bit(NETLINK_F_KERNEL_SOCKET, &nlk->flags); + + 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].release = cfg->release; + nl_table[unit].flags = cfg->flags; + } + 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(sock); + return NULL; +} +EXPORT_SYMBOL(__netlink_kernel_create); + +void +netlink_kernel_release(struct sock *sk) +{ + if (sk == NULL || sk->sk_socket == NULL) + return; + + sock_release(sk->sk_socket); +} +EXPORT_SYMBOL(netlink_kernel_release); + +int __netlink_change_ngroups(struct sock *sk, unsigned int groups) +{ + struct listeners *new, *old; + struct netlink_table *tbl = &nl_table[sk->sk_protocol]; + + if (groups < 32) + groups = 32; + + if (NLGRPSZ(tbl->groups) < NLGRPSZ(groups)) { + new = kzalloc(sizeof(*new) + NLGRPSZ(groups), GFP_ATOMIC); + if (!new) + return -ENOMEM; + old = nl_deref_protected(tbl->listeners); + memcpy(new->masks, old->masks, NLGRPSZ(tbl->groups)); + rcu_assign_pointer(tbl->listeners, new); + + kfree_rcu(old, rcu); + } + tbl->groups = groups; + + return 0; +} + +/** + * netlink_change_ngroups - change number of multicast groups + * + * This changes the number of multicast groups that are available + * on a certain netlink family. Note that it is not possible to + * change the number of groups to below 32. Also note that it does + * not implicitly call netlink_clear_multicast_users() when the + * number of groups is reduced. + * + * @sk: The kernel netlink socket, as returned by netlink_kernel_create(). + * @groups: The new number of groups. + */ +int netlink_change_ngroups(struct sock *sk, unsigned int groups) +{ + int err; + + netlink_table_grab(); + err = __netlink_change_ngroups(sk, groups); + netlink_table_ungrab(); + + return err; +} + +void __netlink_clear_multicast_users(struct sock *ksk, unsigned int group) +{ + struct sock *sk; + struct netlink_table *tbl = &nl_table[ksk->sk_protocol]; + + sk_for_each_bound(sk, &tbl->mc_list) + netlink_update_socket_mc(nlk_sk(sk), group, 0); +} + +struct nlmsghdr * +__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags) +{ + struct nlmsghdr *nlh; + int size = nlmsg_msg_size(len); + + nlh = skb_put(skb, NLMSG_ALIGN(size)); + nlh->nlmsg_type = type; + nlh->nlmsg_len = size; + nlh->nlmsg_flags = flags; + nlh->nlmsg_pid = portid; + nlh->nlmsg_seq = seq; + if (!__builtin_constant_p(size) || NLMSG_ALIGN(size) - size != 0) + memset(nlmsg_data(nlh) + len, 0, NLMSG_ALIGN(size) - size); + return nlh; +} +EXPORT_SYMBOL(__nlmsg_put); + +/* + * It looks a bit ugly. + * It would be better to create kernel thread. + */ + +static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb, + struct netlink_callback *cb, + struct netlink_ext_ack *extack) +{ + struct nlmsghdr *nlh; + + nlh = nlmsg_put_answer(skb, cb, NLMSG_DONE, sizeof(nlk->dump_done_errno), + NLM_F_MULTI | cb->answer_flags); + if (WARN_ON(!nlh)) + return -ENOBUFS; + + nl_dump_check_consistent(cb, nlh); + memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, sizeof(nlk->dump_done_errno)); + + if (extack->_msg && test_bit(NETLINK_F_EXT_ACK, &nlk->flags)) { + nlh->nlmsg_flags |= NLM_F_ACK_TLVS; + if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)) + nlmsg_end(skb, nlh); + } + + return 0; +} + +static int netlink_dump(struct sock *sk) +{ + struct netlink_sock *nlk = nlk_sk(sk); + struct netlink_ext_ack extack = {}; + struct netlink_callback *cb; + struct sk_buff *skb = NULL; + size_t max_recvmsg_len; + struct module *module; + int err = -ENOBUFS; + int alloc_min_size; + int alloc_size; + + mutex_lock(nlk->cb_mutex); + if (!nlk->cb_running) { + err = -EINVAL; + goto errout_skb; + } + + if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) + goto errout_skb; + + /* NLMSG_GOODSIZE is small to avoid high order allocations being + * required, but it makes sense to _attempt_ a 16K bytes allocation + * to reduce number of system calls on dump operations, if user + * ever provided a big enough buffer. + */ + cb = &nlk->cb; + alloc_min_size = max_t(int, cb->min_dump_alloc, NLMSG_GOODSIZE); + + max_recvmsg_len = READ_ONCE(nlk->max_recvmsg_len); + if (alloc_min_size < max_recvmsg_len) { + alloc_size = max_recvmsg_len; + skb = alloc_skb(alloc_size, + (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) | + __GFP_NOWARN | __GFP_NORETRY); + } + if (!skb) { + alloc_size = alloc_min_size; + skb = alloc_skb(alloc_size, GFP_KERNEL); + } + if (!skb) + goto errout_skb; + + /* Trim skb to allocated size. User is expected to provide buffer as + * large as max(min_dump_alloc, 16KiB (mac_recvmsg_len capped at + * netlink_recvmsg())). dump will pack as many smaller messages as + * could fit within the allocated skb. skb is typically allocated + * with larger space than required (could be as much as near 2x the + * requested size with align to next power of 2 approach). Allowing + * dump to use the excess space makes it difficult for a user to have a + * reasonable static buffer based on the expected largest dump of a + * single netdev. The outcome is MSG_TRUNC error. + */ + skb_reserve(skb, skb_tailroom(skb) - alloc_size); + + /* Make sure malicious BPF programs can not read unitialized memory + * from skb->head -> skb->data + */ + skb_reset_network_header(skb); + skb_reset_mac_header(skb); + + netlink_skb_set_owner_r(skb, sk); + + if (nlk->dump_done_errno > 0) { + cb->extack = &extack; + nlk->dump_done_errno = cb->dump(skb, cb); + cb->extack = NULL; + } + + if (nlk->dump_done_errno > 0 || + skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) { + mutex_unlock(nlk->cb_mutex); + + if (sk_filter(sk, skb)) + kfree_skb(skb); + else + __netlink_sendskb(sk, skb); + return 0; + } + + if (netlink_dump_done(nlk, skb, cb, &extack)) + goto errout_skb; + +#ifdef CONFIG_COMPAT_NETLINK_MESSAGES + /* frag_list skb's data is used for compat tasks + * and the regular skb's data for normal (non-compat) tasks. + * See netlink_recvmsg(). + */ + if (unlikely(skb_shinfo(skb)->frag_list)) { + if (netlink_dump_done(nlk, skb_shinfo(skb)->frag_list, cb, &extack)) + goto errout_skb; + } +#endif + + if (sk_filter(sk, skb)) + kfree_skb(skb); + else + __netlink_sendskb(sk, skb); + + if (cb->done) + cb->done(cb); + + WRITE_ONCE(nlk->cb_running, false); + module = cb->module; + skb = cb->skb; + mutex_unlock(nlk->cb_mutex); + module_put(module); + consume_skb(skb); + return 0; + +errout_skb: + mutex_unlock(nlk->cb_mutex); + kfree_skb(skb); + return err; +} + +int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, + const struct nlmsghdr *nlh, + struct netlink_dump_control *control) +{ + struct netlink_callback *cb; + struct netlink_sock *nlk; + struct sock *sk; + int ret; + + refcount_inc(&skb->users); + + sk = netlink_lookup(sock_net(ssk), ssk->sk_protocol, NETLINK_CB(skb).portid); + if (sk == NULL) { + ret = -ECONNREFUSED; + goto error_free; + } + + nlk = nlk_sk(sk); + mutex_lock(nlk->cb_mutex); + /* A dump is in progress... */ + if (nlk->cb_running) { + ret = -EBUSY; + goto error_unlock; + } + /* add reference of module which cb->dump belongs to */ + if (!try_module_get(control->module)) { + ret = -EPROTONOSUPPORT; + goto error_unlock; + } + + cb = &nlk->cb; + memset(cb, 0, sizeof(*cb)); + cb->dump = control->dump; + cb->done = control->done; + cb->nlh = nlh; + cb->data = control->data; + cb->module = control->module; + cb->min_dump_alloc = control->min_dump_alloc; + cb->skb = skb; + + cb->strict_check = nlk_test_bit(STRICT_CHK, NETLINK_CB(skb).sk); + + if (control->start) { + cb->extack = control->extack; + ret = control->start(cb); + cb->extack = NULL; + if (ret) + goto error_put; + } + + WRITE_ONCE(nlk->cb_running, true); + nlk->dump_done_errno = INT_MAX; + + mutex_unlock(nlk->cb_mutex); + + ret = netlink_dump(sk); + + sock_put(sk); + + if (ret) + return ret; + + /* We successfully started a dump, by returning -EINTR we + * signal not to send ACK even if it was requested. + */ + return -EINTR; + +error_put: + module_put(control->module); +error_unlock: + sock_put(sk); + mutex_unlock(nlk->cb_mutex); +error_free: + kfree_skb(skb); + return ret; +} +EXPORT_SYMBOL(__netlink_dump_start); + +static size_t +netlink_ack_tlv_len(struct netlink_sock *nlk, int err, + const struct netlink_ext_ack *extack) +{ + size_t tlvlen; + + if (!extack || !test_bit(NETLINK_F_EXT_ACK, &nlk->flags)) + return 0; + + tlvlen = 0; + if (extack->_msg) + tlvlen += nla_total_size(strlen(extack->_msg) + 1); + if (extack->cookie_len) + tlvlen += nla_total_size(extack->cookie_len); + + /* Following attributes are only reported as error (not warning) */ + if (!err) + return tlvlen; + + if (extack->bad_attr) + tlvlen += nla_total_size(sizeof(u32)); + if (extack->policy) + tlvlen += netlink_policy_dump_attr_size_estimate(extack->policy); + if (extack->miss_type) + tlvlen += nla_total_size(sizeof(u32)); + if (extack->miss_nest) + tlvlen += nla_total_size(sizeof(u32)); + + return tlvlen; +} + +static void +netlink_ack_tlv_fill(struct sk_buff *in_skb, struct sk_buff *skb, + struct nlmsghdr *nlh, int err, + const struct netlink_ext_ack *extack) +{ + if (extack->_msg) + WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)); + if (extack->cookie_len) + WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE, + extack->cookie_len, extack->cookie)); + + if (!err) + return; + + if (extack->bad_attr && + !WARN_ON((u8 *)extack->bad_attr < in_skb->data || + (u8 *)extack->bad_attr >= in_skb->data + in_skb->len)) + WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS, + (u8 *)extack->bad_attr - (u8 *)nlh)); + if (extack->policy) + netlink_policy_dump_write_attr(skb, extack->policy, + NLMSGERR_ATTR_POLICY); + if (extack->miss_type) + WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_TYPE, + extack->miss_type)); + if (extack->miss_nest && + !WARN_ON((u8 *)extack->miss_nest < in_skb->data || + (u8 *)extack->miss_nest > in_skb->data + in_skb->len)) + WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_MISS_NEST, + (u8 *)extack->miss_nest - (u8 *)nlh)); +} + +void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err, + const struct netlink_ext_ack *extack) +{ + struct sk_buff *skb; + struct nlmsghdr *rep; + struct nlmsgerr *errmsg; + size_t payload = sizeof(*errmsg); + struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk); + unsigned int flags = 0; + size_t tlvlen; + + /* Error messages get the original request appened, unless the user + * requests to cap the error message, and get extra error data if + * requested. + */ + if (err && !test_bit(NETLINK_F_CAP_ACK, &nlk->flags)) + payload += nlmsg_len(nlh); + else + flags |= NLM_F_CAPPED; + + tlvlen = netlink_ack_tlv_len(nlk, err, extack); + if (tlvlen) + flags |= NLM_F_ACK_TLVS; + + skb = nlmsg_new(payload + tlvlen, GFP_KERNEL); + if (!skb) + goto err_skb; + + rep = nlmsg_put(skb, NETLINK_CB(in_skb).portid, nlh->nlmsg_seq, + NLMSG_ERROR, sizeof(*errmsg), flags); + if (!rep) + goto err_bad_put; + errmsg = nlmsg_data(rep); + errmsg->error = err; + errmsg->msg = *nlh; + + if (!(flags & NLM_F_CAPPED)) { + if (!nlmsg_append(skb, nlmsg_len(nlh))) + goto err_bad_put; + + memcpy(nlmsg_data(&errmsg->msg), nlmsg_data(nlh), + nlmsg_len(nlh)); + } + + if (tlvlen) + netlink_ack_tlv_fill(in_skb, skb, nlh, err, extack); + + nlmsg_end(skb, rep); + + nlmsg_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid); + + return; + +err_bad_put: + nlmsg_free(skb); +err_skb: + WRITE_ONCE(NETLINK_CB(in_skb).sk->sk_err, ENOBUFS); + sk_error_report(NETLINK_CB(in_skb).sk); +} +EXPORT_SYMBOL(netlink_ack); + +int netlink_rcv_skb(struct sk_buff *skb, int (*cb)(struct sk_buff *, + struct nlmsghdr *, + struct netlink_ext_ack *)) +{ + struct netlink_ext_ack extack; + struct nlmsghdr *nlh; + int err; + + while (skb->len >= nlmsg_total_size(0)) { + int msglen; + + memset(&extack, 0, sizeof(extack)); + nlh = nlmsg_hdr(skb); + err = 0; + + if (nlh->nlmsg_len < NLMSG_HDRLEN || skb->len < nlh->nlmsg_len) + return 0; + + /* Only requests are handled by the kernel */ + if (!(nlh->nlmsg_flags & NLM_F_REQUEST)) + goto ack; + + /* Skip control messages */ + if (nlh->nlmsg_type < NLMSG_MIN_TYPE) + goto ack; + + err = cb(skb, nlh, &extack); + if (err == -EINTR) + goto skip; + +ack: + if (nlh->nlmsg_flags & NLM_F_ACK || err) + netlink_ack(skb, nlh, err, &extack); + +skip: + msglen = NLMSG_ALIGN(nlh->nlmsg_len); + if (msglen > skb->len) + msglen = skb->len; + skb_pull(skb, msglen); + } + + return 0; +} +EXPORT_SYMBOL(netlink_rcv_skb); + +/** + * nlmsg_notify - send a notification netlink message + * @sk: netlink socket to use + * @skb: notification message + * @portid: destination netlink portid for reports or 0 + * @group: destination multicast group or 0 + * @report: 1 to report back, 0 to disable + * @flags: allocation flags + */ +int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid, + unsigned int group, int report, gfp_t flags) +{ + int err = 0; + + if (group) { + int exclude_portid = 0; + + if (report) { + refcount_inc(&skb->users); + exclude_portid = portid; + } + + /* errors reported via destination sk->sk_err, but propagate + * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ + err = nlmsg_multicast(sk, skb, exclude_portid, group, flags); + if (err == -ESRCH) + err = 0; + } + + if (report) { + int err2; + + err2 = nlmsg_unicast(sk, skb, portid); + if (!err) + err = err2; + } + + return err; +} +EXPORT_SYMBOL(nlmsg_notify); + +#ifdef CONFIG_PROC_FS +struct nl_seq_iter { + struct seq_net_private p; + struct rhashtable_iter hti; + int link; +}; + +static void netlink_walk_start(struct nl_seq_iter *iter) +{ + rhashtable_walk_enter(&nl_table[iter->link].hash, &iter->hti); + rhashtable_walk_start(&iter->hti); +} + +static void netlink_walk_stop(struct nl_seq_iter *iter) +{ + rhashtable_walk_stop(&iter->hti); + rhashtable_walk_exit(&iter->hti); +} + +static void *__netlink_seq_next(struct seq_file *seq) +{ + struct nl_seq_iter *iter = seq->private; + struct netlink_sock *nlk; + + do { + for (;;) { + nlk = rhashtable_walk_next(&iter->hti); + + if (IS_ERR(nlk)) { + if (PTR_ERR(nlk) == -EAGAIN) + continue; + + return nlk; + } + + if (nlk) + break; + + netlink_walk_stop(iter); + if (++iter->link >= MAX_LINKS) + return NULL; + + netlink_walk_start(iter); + } + } while (sock_net(&nlk->sk) != seq_file_net(seq)); + + return nlk; +} + +static void *netlink_seq_start(struct seq_file *seq, loff_t *posp) + __acquires(RCU) +{ + struct nl_seq_iter *iter = seq->private; + void *obj = SEQ_START_TOKEN; + loff_t pos; + + iter->link = 0; + + netlink_walk_start(iter); + + for (pos = *posp; pos && obj && !IS_ERR(obj); pos--) + obj = __netlink_seq_next(seq); + + return obj; +} + +static void *netlink_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + ++*pos; + return __netlink_seq_next(seq); +} + +static void netlink_native_seq_stop(struct seq_file *seq, void *v) +{ + struct nl_seq_iter *iter = seq->private; + + if (iter->link >= MAX_LINKS) + return; + + netlink_walk_stop(iter); +} + + +static int netlink_native_seq_show(struct seq_file *seq, void *v) +{ + if (v == SEQ_START_TOKEN) { + seq_puts(seq, + "sk Eth Pid Groups " + "Rmem Wmem Dump Locks Drops Inode\n"); + } else { + struct sock *s = v; + struct netlink_sock *nlk = nlk_sk(s); + + seq_printf(seq, "%pK %-3d %-10u %08x %-8d %-8d %-5d %-8d %-8u %-8lu\n", + s, + s->sk_protocol, + nlk->portid, + nlk->groups ? (u32)nlk->groups[0] : 0, + sk_rmem_alloc_get(s), + sk_wmem_alloc_get(s), + READ_ONCE(nlk->cb_running), + refcount_read(&s->sk_refcnt), + atomic_read(&s->sk_drops), + sock_i_ino(s) + ); + + } + return 0; +} + +#ifdef CONFIG_BPF_SYSCALL +struct bpf_iter__netlink { + __bpf_md_ptr(struct bpf_iter_meta *, meta); + __bpf_md_ptr(struct netlink_sock *, sk); +}; + +DEFINE_BPF_ITER_FUNC(netlink, struct bpf_iter_meta *meta, struct netlink_sock *sk) + +static int netlink_prog_seq_show(struct bpf_prog *prog, + struct bpf_iter_meta *meta, + void *v) +{ + struct bpf_iter__netlink ctx; + + meta->seq_num--; /* skip SEQ_START_TOKEN */ + ctx.meta = meta; + ctx.sk = nlk_sk((struct sock *)v); + return bpf_iter_run_prog(prog, &ctx); +} + +static int netlink_seq_show(struct seq_file *seq, void *v) +{ + struct bpf_iter_meta meta; + struct bpf_prog *prog; + + meta.seq = seq; + prog = bpf_iter_get_info(&meta, false); + if (!prog) + return netlink_native_seq_show(seq, v); + + if (v != SEQ_START_TOKEN) + return netlink_prog_seq_show(prog, &meta, v); + + return 0; +} + +static void netlink_seq_stop(struct seq_file *seq, void *v) +{ + struct bpf_iter_meta meta; + struct bpf_prog *prog; + + if (!v) { + meta.seq = seq; + prog = bpf_iter_get_info(&meta, true); + if (prog) + (void)netlink_prog_seq_show(prog, &meta, v); + } + + netlink_native_seq_stop(seq, v); +} +#else +static int netlink_seq_show(struct seq_file *seq, void *v) +{ + return netlink_native_seq_show(seq, v); +} + +static void netlink_seq_stop(struct seq_file *seq, void *v) +{ + netlink_native_seq_stop(seq, v); +} +#endif + +static const struct seq_operations netlink_seq_ops = { + .start = netlink_seq_start, + .next = netlink_seq_next, + .stop = netlink_seq_stop, + .show = netlink_seq_show, +}; +#endif + +int netlink_register_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&netlink_chain, nb); +} +EXPORT_SYMBOL(netlink_register_notifier); + +int netlink_unregister_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&netlink_chain, nb); +} +EXPORT_SYMBOL(netlink_unregister_notifier); + +static const struct proto_ops netlink_ops = { + .family = PF_NETLINK, + .owner = THIS_MODULE, + .release = netlink_release, + .bind = netlink_bind, + .connect = netlink_connect, + .socketpair = sock_no_socketpair, + .accept = sock_no_accept, + .getname = netlink_getname, + .poll = datagram_poll, + .ioctl = netlink_ioctl, + .listen = sock_no_listen, + .shutdown = sock_no_shutdown, + .setsockopt = netlink_setsockopt, + .getsockopt = netlink_getsockopt, + .sendmsg = netlink_sendmsg, + .recvmsg = netlink_recvmsg, + .mmap = sock_no_mmap, +}; + +static const struct net_proto_family netlink_family_ops = { + .family = PF_NETLINK, + .create = netlink_create, + .owner = THIS_MODULE, /* for consistency 8) */ +}; + +static int __net_init netlink_net_init(struct net *net) +{ +#ifdef CONFIG_PROC_FS + if (!proc_create_net("netlink", 0, net->proc_net, &netlink_seq_ops, + sizeof(struct nl_seq_iter))) + return -ENOMEM; +#endif + return 0; +} + +static void __net_exit netlink_net_exit(struct net *net) +{ +#ifdef CONFIG_PROC_FS + remove_proc_entry("netlink", net->proc_net); +#endif +} + +static void __init netlink_add_usersock_entry(void) +{ + struct listeners *listeners; + int groups = 32; + + listeners = kzalloc(sizeof(*listeners) + NLGRPSZ(groups), GFP_KERNEL); + if (!listeners) + panic("netlink_add_usersock_entry: Cannot allocate listeners\n"); + + netlink_table_grab(); + + nl_table[NETLINK_USERSOCK].groups = groups; + rcu_assign_pointer(nl_table[NETLINK_USERSOCK].listeners, listeners); + nl_table[NETLINK_USERSOCK].module = THIS_MODULE; + nl_table[NETLINK_USERSOCK].registered = 1; + nl_table[NETLINK_USERSOCK].flags = NL_CFG_F_NONROOT_SEND; + + netlink_table_ungrab(); +} + +static struct pernet_operations __net_initdata netlink_net_ops = { + .init = netlink_net_init, + .exit = netlink_net_exit, +}; + +static inline u32 netlink_hash(const void *data, u32 len, u32 seed) +{ + const struct netlink_sock *nlk = data; + struct netlink_compare_arg arg; + + netlink_compare_arg_init(&arg, sock_net(&nlk->sk), nlk->portid); + return jhash2((u32 *)&arg, netlink_compare_arg_len / sizeof(u32), seed); +} + +static const struct rhashtable_params netlink_rhashtable_params = { + .head_offset = offsetof(struct netlink_sock, node), + .key_len = netlink_compare_arg_len, + .obj_hashfn = netlink_hash, + .obj_cmpfn = netlink_compare, + .automatic_shrinking = true, +}; + +#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) +BTF_ID_LIST(btf_netlink_sock_id) +BTF_ID(struct, netlink_sock) + +static const struct bpf_iter_seq_info netlink_seq_info = { + .seq_ops = &netlink_seq_ops, + .init_seq_private = bpf_iter_init_seq_net, + .fini_seq_private = bpf_iter_fini_seq_net, + .seq_priv_size = sizeof(struct nl_seq_iter), +}; + +static struct bpf_iter_reg netlink_reg_info = { + .target = "netlink", + .ctx_arg_info_size = 1, + .ctx_arg_info = { + { offsetof(struct bpf_iter__netlink, sk), + PTR_TO_BTF_ID_OR_NULL }, + }, + .seq_info = &netlink_seq_info, +}; + +static int __init bpf_iter_register(void) +{ + netlink_reg_info.ctx_arg_info[0].btf_id = *btf_netlink_sock_id; + return bpf_iter_reg_target(&netlink_reg_info); +} +#endif + +static int __init netlink_proto_init(void) +{ + int i; + int err = proto_register(&netlink_proto, 0); + + if (err != 0) + goto out; + +#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS) + err = bpf_iter_register(); + if (err) + goto out; +#endif + + BUILD_BUG_ON(sizeof(struct netlink_skb_parms) > sizeof_field(struct sk_buff, cb)); + + nl_table = kcalloc(MAX_LINKS, sizeof(*nl_table), GFP_KERNEL); + if (!nl_table) + goto panic; + + for (i = 0; i < MAX_LINKS; i++) { + if (rhashtable_init(&nl_table[i].hash, + &netlink_rhashtable_params) < 0) { + while (--i > 0) + rhashtable_destroy(&nl_table[i].hash); + kfree(nl_table); + goto panic; + } + } + + netlink_add_usersock_entry(); + + sock_register(&netlink_family_ops); + register_pernet_subsys(&netlink_net_ops); + register_pernet_subsys(&netlink_tap_net_ops); + /* The netlink device handler may be needed early. */ + rtnetlink_init(); +out: + return err; +panic: + panic("netlink_init: Cannot allocate nl_table\n"); +} + +core_initcall(netlink_proto_init); 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