Re: [PATCH] fix small DoS on connect() (was Re: BUG: Unusual TCP Connect() results.)

* Herbert Xu [off-list ref] 2005-06-12 22:06

On Sun, Jun 12, 2005 at 01:40:39PM +0200, Willy Tarreau wrote:

quoted

Sorry Herbert, but both RFC793 page 32 figure 9 and my Linux box disagree
with this statement. Look: at line 5, A rejects the SYN-ACK because the
ACK is wrong during the session setup.

Look at the first check inside th->ack in tcp_rcv_synsent_state_process.

Usually a continious flow of ACK+RST is used to prevent a connection
from being established, it's more reliable because even if you hit the
ISS+rcv_next window the connection attempt will still be reset.