Commit 293a1991 authored Dec 20, 2017 by Haishuang Yan Committed by David S. Miller Dec 20, 2017

ip6_gre: fix a pontential issue in ip6erspan_rcv



pskb_may_pull() can change skb->data, so we need to load ipv6h/ershdr at
the right place.

Fixes: 5a963eb6 ("ip6_gre: Add ERSPAN native tunnel support")
Cc: William Tu <u9012063@gmail.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 9a07ae68

net/ipv6/ip6_gre.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -507,12 +507,11 @@ static int ip6erspan_rcv(struct sk_buff *skb, int gre_hdr_len,
		struct ip6_tnl *tunnel;
		u8 ver;

		ipv6h = ipv6_hdr(skb);
		ershdr = (struct erspan_base_hdr *)skb->data;

		if (unlikely(!pskb_may_pull(skb, sizeof(*ershdr))))
		return PACKET_REJECT;

		ipv6h = ipv6_hdr(skb);
		ershdr = (struct erspan_base_hdr *)skb->data;
		ver = (ntohs(ershdr->ver_vlan) & VER_MASK) >> VER_OFFSET;
		tpi->key = cpu_to_be32(ntohs(ershdr->session_id) & ID_MASK);