[PATCH 3.8 24/81] tuntap: correctly handle error in tun_set_iff()

From: Kamal Mostafa
Date: Tue Oct 29 2013 - 14:10:09 EST -stable review patch. If anyone has any objections, please let me know.


From: Jason Wang <jasowang@xxxxxxxxxx>

commit 662ca437e714caaab855b12415d6ffd815985bc0 upstream.

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@xxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[ kamal: 3.8-stable for CVE-2013-4343 ]
Cc: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
drivers/net/tun.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 441c987..66b4613 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1686,11 +1686,11 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
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) ||
@@ -1734,7 +1734,12 @@ 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:
+ tun_detach_all(dev);
+ tun_flow_uninit(tun);
+ security_tun_dev_free_security(tun->security);
return err;

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