From patchwork Thu May 31 22:58:54 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [1/1, CVE-2012-2663, HARDY, LUCID, NATTY, ONEIRIC, PRECISE] tcp: drop SYN+FIN messages Date: Thu, 31 May 2012 12:58:54 -0000 From: Brad Figg X-Patchwork-Id: 162242 Message-Id: <1338505134-539-2-git-send-email-brad.figg@canonical.com> To: kernel-team@lists.ubuntu.com From: Eric Dumazet CVE-2012-2663 BugLink: http://bugs.launchpad.net/bugs/1007091 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 (cherry picked from commit fdf5af0daf8019cec2396cdef8fb042d80fe71fa) Signed-off-by: Brad Figg --- net/ipv4/tcp_input.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 78dd38c..0cbb440 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;