tuntap: correctly handle error in tun_set_iff()

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>

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index a639de8401f8..807815fc9968 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1641,11 +1641,11 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                 INIT_LIST_HEAD(&tun->disabled);
                 err = tun_attach(tun, file, false);
                 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) ||
@@ -1689,7 +1689,12 @@ 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;
 }