diff --git a/drivers/net/tun.c b/drivers/net/tun.c index d242e62da3fb..e0e2061f44b3 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++; @@ -1751,7 +1753,7 @@ 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; @@ -1839,13 +1841,17 @@ 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); @@ -1989,7 +1995,7 @@ 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)