diff options
Diffstat (limited to 'drivers/net/tun.c')
-rw-r--r-- | drivers/net/tun.c | 70 |
1 files changed, 47 insertions, 23 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 24cc94453d38..44b16d945e33 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -627,7 +627,8 @@ static void tun_detach_all(struct net_device *dev) module_put(THIS_MODULE); } -static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter) +static int tun_attach(struct tun_struct *tun, struct file *file, + bool skip_filter, bool publish_tun) { struct tun_file *tfile = file->private_data; struct net_device *dev = tun->dev; @@ -669,7 +670,8 @@ static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filte tfile->queue_index = tun->numqueues; tfile->socket.sk->sk_shutdown &= ~RCV_SHUTDOWN; - rcu_assign_pointer(tfile->tun, tun); + if (publish_tun) + rcu_assign_pointer(tfile->tun, tun); rcu_assign_pointer(tun->tfiles[tun->numqueues], tfile); tun->numqueues++; @@ -828,18 +830,8 @@ static void tun_net_uninit(struct net_device *dev) /* Net device open. */ static int tun_net_open(struct net_device *dev) { - struct tun_struct *tun = netdev_priv(dev); - int i; - netif_tx_start_all_queues(dev); - for (i = 0; i < tun->numqueues; i++) { - struct tun_file *tfile; - - tfile = rtnl_dereference(tun->tfiles[i]); - tfile->socket.sk->sk_write_space(tfile->socket.sk); - } - return 0; } @@ -1114,6 +1106,13 @@ static void tun_net_init(struct net_device *dev) } } +static bool tun_sock_writeable(struct tun_struct *tun, struct tun_file *tfile) +{ + struct sock *sk = tfile->socket.sk; + + return (tun->dev->flags & IFF_UP) && sock_writeable(sk); +} + /* Character device part */ /* Poll */ @@ -1136,10 +1135,14 @@ static unsigned int tun_chr_poll(struct file *file, poll_table *wait) if (!skb_array_empty(&tfile->tx_array)) mask |= POLLIN | POLLRDNORM; - if (tun->dev->flags & IFF_UP && - (sock_writeable(sk) || - (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) && - sock_writeable(sk)))) + /* Make sure SOCKWQ_ASYNC_NOSPACE is set if not writable to + * guarantee EPOLLOUT to be raised by either here or + * tun_sock_write_space(). Then process could get notification + * after it writes to a down device and meets -EIO. + */ + if (tun_sock_writeable(tun, tfile) || + (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags) && + tun_sock_writeable(tun, tfile))) mask |= POLLOUT | POLLWRNORM; if (tun->dev->reg_state != NETREG_REGISTERED) @@ -1194,9 +1197,6 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, u32 rxhash; ssize_t n; - if (!(tun->dev->flags & IFF_UP)) - return -EIO; - if (!(tun->flags & IFF_NO_PI)) { if (len < sizeof(pi)) return -EINVAL; @@ -1273,9 +1273,11 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, err = skb_copy_datagram_from_iter(skb, 0, from, len); if (err) { + err = -EFAULT; +drop: this_cpu_inc(tun->pcpu_stats->rx_dropped); kfree_skb(skb); - return -EFAULT; + return err; } err = virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun)); @@ -1327,7 +1329,16 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, skb_probe_transport_header(skb, 0); rxhash = skb_get_hash(skb); + + rcu_read_lock(); + if (unlikely(!(tun->dev->flags & IFF_UP))) { + err = -EIO; + rcu_read_unlock(); + goto drop; + } + netif_rx_ni(skb); + rcu_read_unlock(); stats = get_cpu_ptr(tun->pcpu_stats); u64_stats_update_begin(&stats->syncp); @@ -1753,7 +1764,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) if (err < 0) return err; - err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER); + err = tun_attach(tun, file, ifr->ifr_flags & IFF_NOFILTER, true); if (err < 0) return err; @@ -1841,13 +1852,17 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) NETIF_F_HW_VLAN_STAG_TX); INIT_LIST_HEAD(&tun->disabled); - err = tun_attach(tun, file, false); + err = tun_attach(tun, file, false, false); if (err < 0) goto err_free_flow; err = register_netdevice(tun->dev); if (err < 0) goto err_detach; + /* free_netdev() won't check refcnt, to aovid race + * with dev_put() we need publish tun after registration. + */ + rcu_assign_pointer(tfile->tun, tun); } netif_carrier_on(tun->dev); @@ -1991,7 +2006,7 @@ static int tun_set_queue(struct file *file, struct ifreq *ifr) ret = security_tun_dev_attach_queue(tun->security); if (ret < 0) goto unlock; - ret = tun_attach(tun, file, false); + ret = tun_attach(tun, file, false, true); } else if (ifr->ifr_flags & IFF_DETACH_QUEUE) { tun = rtnl_dereference(tfile->tun); if (!tun || !(tun->flags & IFF_MULTI_QUEUE) || tfile->detached) @@ -2526,6 +2541,7 @@ static int tun_device_event(struct notifier_block *unused, { struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct tun_struct *tun = netdev_priv(dev); + int i; if (dev->rtnl_link_ops != &tun_link_ops) return NOTIFY_DONE; @@ -2535,6 +2551,14 @@ static int tun_device_event(struct notifier_block *unused, if (tun_queue_resize(tun)) return NOTIFY_BAD; break; + case NETDEV_UP: + for (i = 0; i < tun->numqueues; i++) { + struct tun_file *tfile; + + tfile = rtnl_dereference(tun->tfiles[i]); + tfile->socket.sk->sk_write_space(tfile->socket.sk); + } + break; default: break; } |