From: Andi Kleen <ak@suse.de>
To: Pekka Savola <pekkas@netcore.fi>
Cc: netdev@oss.sgi.com
Subject: Re: Ambiguities in TCP/IP - firewall bypassing (fwd)
Date: Sun, 20 Oct 2002 06:35:35 +0200 [thread overview]
Message-ID: <20021020063535.A6016@wotan.suse.de> (raw)
In-Reply-To: <Pine.LNX.4.44.0210191437230.12141-100000@netcore.fi>
On Sat, Oct 19, 2002 at 02:38:56PM +0300, Pekka Savola wrote:
> See the thread on bugtraq.
>
> Linux 2.4.19 initiates TCP handshake with SYN and RST bits set. SYN with
> _RST_ seems like a total nonsense (SYN with FIN might even be useful for
> stuff like T/TCP) but I guess the spec didn't take any stance on that..
Here is a patch to fix it for 2.4.19.
--- linux/net/ipv4/tcp_input.c-o 2002-10-15 17:24:53.000000000 +0200
+++ linux/net/ipv4/tcp_input.c 2002-10-20 06:34:05.000000000 +0200
@@ -3664,6 +3664,9 @@
goto discard;
case TCP_LISTEN:
+ if(th->rst)
+ goto discard;
+
if(th->ack)
return 1;
-Andi
next prev parent reply other threads:[~2002-10-20 4:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-19 11:38 Ambiguities in TCP/IP - firewall bypassing (fwd) Pekka Savola
2002-10-20 4:35 ` Andi Kleen [this message]
2002-10-30 17:16 ` Pekka Savola
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