vxlan: fix a use after free in vxlan_encap_bypass

when netif_rx() is done, the netif_rx handled skb maybe be freed,
and should not be used.

Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 2a51e6e48e1e..faf1bd1f1ecf 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1668,6 +1668,8 @@ static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan,
         struct pcpu_sw_netstats *tx_stats, *rx_stats;
         union vxlan_addr loopback;
         union vxlan_addr *remote_ip = &dst_vxlan->default_dst.remote_ip;
+        struct net_device *dev = skb->dev;
+        int len = skb->len;
 
         tx_stats = this_cpu_ptr(src_vxlan->dev->tstats);
         rx_stats = this_cpu_ptr(dst_vxlan->dev->tstats);
@@ -1691,16 +1693,16 @@ static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan,
 
         u64_stats_update_begin(&tx_stats->syncp);
         tx_stats->tx_packets++;
-        tx_stats->tx_bytes += skb->len;
+        tx_stats->tx_bytes += len;
         u64_stats_update_end(&tx_stats->syncp);
 
         if (netif_rx(skb) == NET_RX_SUCCESS) {
                 u64_stats_update_begin(&rx_stats->syncp);
                 rx_stats->rx_packets++;
-                rx_stats->rx_bytes += skb->len;
+                rx_stats->rx_bytes += len;
                 u64_stats_update_end(&rx_stats->syncp);
         } else {
-                skb->dev->stats.rx_dropped++;
+                dev->stats.rx_dropped++;
         }
 }