diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 113f44429982..cb97fda1b6df 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -49,13 +49,16 @@ EXPORT_SYMBOL(secpath_dup);
 int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
 {
 	int offset, offset_seq;
+	int hlen;
 
 	switch (nexthdr) {
 	case IPPROTO_AH:
+		hlen = sizeof(struct ip_auth_hdr);
 		offset = offsetof(struct ip_auth_hdr, spi);
 		offset_seq = offsetof(struct ip_auth_hdr, seq_no);
 		break;
 	case IPPROTO_ESP:
+		hlen = sizeof(struct ip_esp_hdr);
 		offset = offsetof(struct ip_esp_hdr, spi);
 		offset_seq = offsetof(struct ip_esp_hdr, seq_no);
 		break;
@@ -69,7 +72,7 @@ int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq)
 		return 1;
 	}
 
-	if (!pskb_may_pull(skb, 16))
+	if (!pskb_may_pull(skb, hlen))
 		return -EINVAL;
 
 	*spi = *(__be32*)(skb_transport_header(skb) + offset);