From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Bloch Subject: [net] vxlan: fix use-after-free on deletion Date: Thu, 1 Jun 2017 11:43:35 +0300 Message-ID: <1496306615-770-1-git-send-email-markb@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain Cc: To: , Return-path: Received: from mail-he1eur01on0041.outbound.protection.outlook.com ([104.47.0.41]:14368 "EHLO EUR01-HE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751563AbdFAInp (ORCPT ); Thu, 1 Jun 2017 04:43:45 -0400 Sender: netdev-owner@vger.kernel.org List-ID: 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(). Signed-off-by: Mark Bloch --- 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 328b471..f6a4310 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -59,6 +59,8 @@ 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; @@ -1067,6 +1069,8 @@ 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); @@ -2342,6 +2346,15 @@ 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); @@ -3286,15 +3299,9 @@ 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); -- 1.8.4.3