From fdf5af0daf8019cec2396cdef8fb042d80fe71fa Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 2 Dec 2011 23:41:42 +0000 Subject: tcp: drop SYN+FIN messages Denys Fedoryshchenko reported that SYN+FIN attacks were bringing his linux machines to their limits. Dont call conn_request() if the TCP flags includes SYN flag Reported-by: Denys Fedoryshchenko Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp_input.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/ipv4/tcp_input.c') diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 78dd38cd5496..0cbb44076cfa 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5811,6 +5811,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, goto discard; if (th->syn) { + if (th->fin) + goto discard; if (icsk->icsk_af_ops->conn_request(sk, skb) < 0) return 1; -- cgit v1.2.3-55-g7522