tcp: drop SYN+FIN messages

commit fdf5af0daf upstream.

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 <denys@visp.net.lb>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric Dumazet
2011-12-02 23:41:42 +00:00
committed by Greg Kroah-Hartman
parent 9c5d9de68e
commit 1a4eda9788

View File

@@ -5761,6 +5761,8 @@ 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;