| Date | Tue, 02 Oct 2012 00:54:19 +0200 | From | Willy Tarreau <> | Subject | [ 142/180] tcp: drop SYN+FIN messages |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <eric.dumazet@gmail.com>
commit fdf5af0daf8019cec2396cdef8fb042d80fe71fa 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> Signed-off-by: Willy Tarreau <w@1wt.eu> --- net/ipv4/tcp_input.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 4b148e5..db755c4 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5634,6 +5634,8 @@ 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; -- 1.7.2.1.45.g54fbc
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