vxlan: Fix double free of skb.

In case of error vxlan_xmit_one() can free already freed skb.
Also fixes memory leak of dst-entry.

Fixes: acbf74a7630 ("vxlan: Refactor vxlan driver to make use
of the common UDP tunnel functions").

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 10 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 49d9f2291998..7fbd89fbe107 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1579,8 +1579,10 @@ static int vxlan6_xmit_skb(struct vxlan_sock *vs,
         bool udp_sum = !udp_get_no_check6_tx(vs->sock->sk);
 
         skb = udp_tunnel_handle_offloads(skb, udp_sum);
-        if (IS_ERR(skb))
-                return -EINVAL;
+        if (IS_ERR(skb)) {
+                err = -EINVAL;
+                goto err;
+        }
 
         skb_scrub_packet(skb, xnet);
 
@@ -1590,12 +1592,16 @@ static int vxlan6_xmit_skb(struct vxlan_sock *vs,
 
         /* Need space for new headers (invalidates iph ptr) */
         err = skb_cow_head(skb, min_headroom);
-        if (unlikely(err))
-                return err;
+        if (unlikely(err)) {
+                kfree_skb(skb);
+                goto err;
+        }
 
         skb = vlan_hwaccel_push_inside(skb);
-        if (WARN_ON(!skb))
-                return -ENOMEM;
+        if (WARN_ON(!skb)) {
+                err = -ENOMEM;
+                goto err;
+        }
 
         vxh = (struct vxlanhdr *) __skb_push(skb, sizeof(*vxh));
         vxh->vx_flags = htonl(VXLAN_FLAGS);
@@ -1606,6 +1612,9 @@ static int vxlan6_xmit_skb(struct vxlan_sock *vs,
         udp_tunnel6_xmit_skb(vs->sock, dst, skb, dev, saddr, daddr, prio,
                              ttl, src_port, dst_port);
         return 0;
+err:
+        dst_release(dst);
+        return err;
 }
 #endif
 
@@ -1621,7 +1630,7 @@ int vxlan_xmit_skb(struct vxlan_sock *vs,
 
         skb = udp_tunnel_handle_offloads(skb, udp_sum);
         if (IS_ERR(skb))
-                return -EINVAL;
+                return PTR_ERR(skb);
 
         min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
                         + VXLAN_HLEN + sizeof(struct iphdr)
@@ -1629,8 +1638,10 @@ int vxlan_xmit_skb(struct vxlan_sock *vs,
 
         /* Need space for new headers (invalidates iph ptr) */
         err = skb_cow_head(skb, min_headroom);
-        if (unlikely(err))
+        if (unlikely(err)) {
+                kfree_skb(skb);
                 return err;
+        }
 
         skb = vlan_hwaccel_push_inside(skb);
         if (WARN_ON(!skb))
@@ -1776,9 +1787,12 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
                                      tos, ttl, df, src_port, dst_port,
                                      htonl(vni << 8),
                                      !net_eq(vxlan->net, dev_net(vxlan->dev)));
-
-                if (err < 0)
+                if (err < 0) {
+                        /* skb is already freed. */
+                        skb = NULL;
                         goto rt_tx_error;
+                }
+
                 iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 #if IS_ENABLED(CONFIG_IPV6)
         } else {