xfrm: Verify MAC header exists before overwriting eth_hdr(skb)->h_proto

[mirror_ubuntu-bionic-kernel.git] / net / ipv4 / xfrm4_mode_tunnel.c

diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
index 20ca486b3cadf34c2e4fa6df17d44a178fbe3ddc..acdde9df8a3ce973025a0ff9bbf6bc7515250060 100644 (file)
--- a/net/ipv4/xfrm4_mode_tunnel.c
+++ b/net/ipv4/xfrm4_mode_tunnel.c
@@ -92,7 +92,8 @@ static int xfrm4_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
 
        skb_reset_network_header(skb);
        skb_mac_header_rebuild(skb);
-       eth_hdr(skb)->h_proto = skb->protocol;
+       if (skb->mac_len)
+               eth_hdr(skb)->h_proto = skb->protocol;
 
        err = 0;