diff mbox series

[net] macvlan: Fix one possible double free

Message ID 1514295872-120876-1-git-send-email-gfree.wind@vip.163.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series [net] macvlan: Fix one possible double free | expand

Commit Message

Gao Feng Dec. 26, 2017, 1:44 p.m. UTC 
From: Gao Feng <gfree.wind@vip.163.com>

Because the macvlan_uninit would free the macvlan port, so there is one
double free case in macvlan_common_newlink. When the macvlan port is just
created, then register_netdevice or netdev_upper_dev_link failed and they
would invoke macvlan_uninit. Then it would reach the macvlan_port_destroy
which triggers the double free.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
---
 drivers/net/macvlan.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

David Miller Jan. 2, 2018, 6:30 p.m. UTC | #1 
aFrom: gfree.wind@vip.163.com
Date: Tue, 26 Dec 2017 21:44:32 +0800

> From: Gao Feng <gfree.wind@vip.163.com>
> 
> Because the macvlan_uninit would free the macvlan port, so there is one
> double free case in macvlan_common_newlink. When the macvlan port is just
> created, then register_netdevice or netdev_upper_dev_link failed and they
> would invoke macvlan_uninit. Then it would reach the macvlan_port_destroy
> which triggers the double free.
> 
> Signed-off-by: Gao Feng <gfree.wind@vip.163.com>

Applied.
diff mbox series

Patch

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index a178c5e..a0f2be8 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -1444,9 +1444,14 @@  int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
 	return 0;
 
 unregister_netdev:
+	/* macvlan_uninit would free the macvlan port */
 	unregister_netdevice(dev);
+	return err;
 destroy_macvlan_port:
-	if (create)
+	/* the macvlan port may be freed by macvlan_uninit when fail to register.
+	 * so we destroy the macvlan port only when it's valid.
+	 */
+	if (create && macvlan_port_get_rtnl(dev))
 		macvlan_port_destroy(port->dev);
 	return err;
 }