From 1245dfc8cadb258386fcd27df38215a0eccb1f17 Mon Sep 17 00:00:00 2001 From: Li RongQing Date: Fri, 17 Oct 2014 16:53:23 +0800 Subject: [PATCH] ipv4: fix a potential use after free in ip_tunnel_core.c pskb_may_pull() maybe change skb->data and make eth pointer oboslete, so set eth after pskb_may_pull() Fixes:3d7b46cd("ip_tunnel: push generic protocol handling to ip_tunnel module") Cc: Pravin B Shelar Signed-off-by: Li RongQing Acked-by: Pravin B Shelar Signed-off-by: David S. Miller --- net/ipv4/ip_tunnel_core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c index f4c987bb7e94..88c386cf7d85 100644 --- a/net/ipv4/ip_tunnel_core.c +++ b/net/ipv4/ip_tunnel_core.c @@ -91,11 +91,12 @@ int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto) skb_pull_rcsum(skb, hdr_len); if (inner_proto == htons(ETH_P_TEB)) { - struct ethhdr *eh = (struct ethhdr *)skb->data; + struct ethhdr *eh; if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) return -ENOMEM; + eh = (struct ethhdr *)skb->data; if (likely(ntohs(eh->h_proto) >= ETH_P_802_3_MIN)) skb->protocol = eh->h_proto; else -- 2.20.1