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path: root/drivers/net/tun.c
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Diffstat (limited to 'drivers/net/tun.c')
-rw-r--r--drivers/net/tun.c70
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;
}