tuntap: correctly handle error in tun_set_iff()

[ Upstream commit 662ca437e714caaab855b12415d6ffd815985bc0 ]

Commit c8d68e6be1c3b242f1c598595830890b65cea64a
(tuntap: multiqueue support) only call free_netdev() on error in
tun_set_iff(). This causes several issues:

- memory of tun security were leaked
- use after free since the flow gc timer was not deleted and the tfile
  were not detached

This patch solves the above issues.

Reported-by: Wannes Rombouts <wannes.rombouts@epitech.eu>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 7b54f4f052d085a106dba118ad6c4d1c6e41eacb..b18ead556994cd525aae3ab1ed03cd938a287263 100644 (file)
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1693,11 +1693,11 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                INIT_LIST_HEAD(&tun->disabled);
                err = tun_attach(tun, file);
                if (err < 0)
-                       goto err_free_dev;
+                       goto err_free_flow;
 
                err = register_netdevice(tun->dev);
                if (err < 0)
-                       goto err_free_dev;
+                       goto err_detach;
 
                if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
                    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
@@ -1741,7 +1741,12 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
        strcpy(ifr->ifr_name, tun->dev->name);
        return 0;
 
- err_free_dev:
+err_detach:
+       tun_detach_all(dev);
+err_free_flow:
+       tun_flow_uninit(tun);
+       security_tun_dev_free_security(tun->security);
+err_free_dev:
        free_netdev(dev);
        return err;
 }