Merge branch 'erspan-a-couple-fixes'

William Tu says:

====================
net: erspan: a couple fixes

Haishuang Yan reports a couple of issues (wrong return value,
pskb_may_pull) on erspan V1.  Since erspan V2 is in net-next,
this series fix the similar issues on v2.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_gre.c

@@ -279,7 +279,6 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 	 * Use ERSPAN 10-bit session ID as key.
 	 */
 	tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
-	pkt_md = (struct erspan_metadata *)(ershdr + 1);
 	tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
 				  tpi->flags | TUNNEL_KEY,
 				  iph->saddr, iph->daddr, tpi->key);
@@ -287,7 +286,10 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 	if (tunnel) {
 		len = gre_hdr_len + erspan_hdr_len(ver);
 		if (unlikely(!pskb_may_pull(skb, len)))
-			return -ENOMEM;
+			return PACKET_REJECT;
+
+		ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
+		pkt_md = (struct erspan_metadata *)(ershdr + 1);
 
 		if (__iptunnel_pull_header(skb,
 					   len,

net/ipv6/ip6_gre.c

@@ -515,7 +515,6 @@ static int ip6erspan_rcv(struct sk_buff *skb, int gre_hdr_len,
 
 	ver = (ntohs(ershdr->ver_vlan) & VER_MASK) >> VER_OFFSET;
 	tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);
-	pkt_md = (struct erspan_metadata *)(ershdr + 1);
 
 	tunnel = ip6gre_tunnel_lookup(skb->dev,
 				      &ipv6h->saddr, &ipv6h->daddr, tpi->key,
@@ -524,7 +523,10 @@ static int ip6erspan_rcv(struct sk_buff *skb, int gre_hdr_len,
 		int len = erspan_hdr_len(ver);
 
 		if (unlikely(!pskb_may_pull(skb, len)))
-			return -ENOMEM;
+			return PACKET_REJECT;
+
+		ershdr = (struct erspan_base_hdr *)skb->data;
+		pkt_md = (struct erspan_metadata *)(ershdr + 1);
 
 		if (__iptunnel_pull_header(skb, len,
 					   htons(ETH_P_TEB),