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Commit a53cb29b authored by Mark Bloch's avatar Mark Bloch Committed by David S. Miller
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vxlan: fix use-after-free on deletion 



Adding a vxlan interface to a socket isn't symmetrical, while adding
is done in vxlan_open() the deletion is done in vxlan_dellink().
This can cause a use-after-free error when we close the vxlan
interface before deleting it.

We add vxlan_vs_del_dev() to match vxlan_vs_add_dev() and call
it from vxlan_stop() to match the call from vxlan_open().

Fixes: 56ef9c90 ("vxlan: Move socket initialization to within rtnl scope")
Acked-by: default avatarJiri Benc <jbenc@redhat.com>
Tested-by: default avatarRoi Dayan <roid@mellanox.com>
Signed-off-by: default avatarMark Bloch <markb@mellanox.com>
Acked-by: default avatarRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 78b07ac1

drivers/net/vxlan.c

+13 −6
Original line number Diff line number Diff line
@@ -59,6 +59,8 @@ static const u8 all_zeros_mac[ETH_ALEN + 2]; 


static int vxlan_sock_add(struct vxlan_dev *vxlan);



static void vxlan_vs_del_dev(struct vxlan_dev *vxlan);



/* per-network namespace private data for this module */

struct vxlan_net {

	struct list_head  vxlan_list;
@@ -1081,6 +1083,8 @@ static void vxlan_sock_release(struct vxlan_dev *vxlan) 
	rcu_assign_pointer(vxlan->vn4_sock, NULL);

	synchronize_net();



	vxlan_vs_del_dev(vxlan);



	if (__vxlan_sock_release_prep(sock4)) {

		udp_tunnel_sock_release(sock4->sock);

		kfree(sock4);
@@ -2356,6 +2360,15 @@ static void vxlan_cleanup(unsigned long arg) 
	mod_timer(&vxlan->age_timer, next_timer);

}



static void vxlan_vs_del_dev(struct vxlan_dev *vxlan)

{

	struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);



	spin_lock(&vn->sock_lock);

	hlist_del_init_rcu(&vxlan->hlist);

	spin_unlock(&vn->sock_lock);

}



static void vxlan_vs_add_dev(struct vxlan_sock *vs, struct vxlan_dev *vxlan)

{

	struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);
@@ -3300,15 +3313,9 @@ static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[], 
static void vxlan_dellink(struct net_device *dev, struct list_head *head)

{

	struct vxlan_dev *vxlan = netdev_priv(dev);

	struct vxlan_net *vn = net_generic(vxlan->net, vxlan_net_id);



	vxlan_flush(vxlan, true);



	spin_lock(&vn->sock_lock);

	if (!hlist_unhashed(&vxlan->hlist))

		hlist_del_rcu(&vxlan->hlist);

	spin_unlock(&vn->sock_lock);



	gro_cells_destroy(&vxlan->gro_cells);

	list_del(&vxlan->next);

	unregister_netdevice_queue(dev, head);