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authorEric Dumazet <eric.dumazet@gmail.com>2011-12-02 23:41:42 +0000
committerDavid S. Miller <davem@davemloft.net>2011-12-04 01:25:19 -0500
commitfdf5af0daf8019cec2396cdef8fb042d80fe71fa (patch)
tree2423b611659756f2b6553b8d1aa2c117b248c884 /net/ipv4
parent78a8a36fe0b2cee5a0a7360107815cbcad5b4003 (diff)
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 <denys@visp.net.lb> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_input.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 78dd38cd549..0cbb44076cf 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;