ipv4: fix a potential use after free in fou.c

pskb_may_pull() maybe change skb->data and make uh pointer oboslete,
so reload uh and guehdr

Fixes: 37dd0247 ("gue: Receive side for Generic UDP Encapsulation")
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Li RongQing 2014-10-17 16:53:47 +08:00 committed by David S. Miller
parent 1245dfc8ca
commit d8f00d2710

View File

@ -87,6 +87,9 @@ static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
if (!pskb_may_pull(skb, len))
goto drop;
uh = udp_hdr(skb);
guehdr = (struct guehdr *)&uh[1];
if (guehdr->version != 0)
goto drop;