diff --git a/net/ipv4/tunnel4.c b/net/ipv4/tunnel4.c
index d3b709a..cb1f0e8 100644
--- a/net/ipv4/tunnel4.c
+++ b/net/ipv4/tunnel4.c
@@ -97,7 +97,7 @@
 {
 	struct xfrm_tunnel *handler;
 
-	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 		goto drop;
 
 	for (handler = tunnel64_handlers; handler; handler = handler->next)