From a53cb29b0af346af44e4abf13d7e59f807fba690 Mon Sep 17 00:00:00 2001 From: Mark Bloch Date: Fri, 2 Jun 2017 03:24:08 +0300 Subject: [PATCH] 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: 56ef9c909b40 ("vxlan: Move socket initialization to within rtnl scope") Acked-by: Jiri Benc Tested-by: Roi Dayan Signed-off-by: Mark Bloch Acked-by: Roopa Prabhu Signed-off-by: David S. Miller --- drivers/net/vxlan.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 5c1d69e37870..a6b5052c1d36 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -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); -- 2.20.1