From 293a1991cf0d62d0a60b41af42f1dd601d5029fc Mon Sep 17 00:00:00 2001 From: Haishuang Yan Date: Wed, 20 Dec 2017 09:53:19 +0800 Subject: [PATCH] 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: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support") Cc: William Tu Acked-by: William Tu Signed-off-by: Haishuang Yan Signed-off-by: David S. Miller --- net/ipv6/ip6_gre.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index 87b9892..9bd1103 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -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); -- 2.7.4