Bugtraq mailing list archives
Re: Broadcast and multi-homed routing condition in TCP/IP stack.
From: "Charles M. Hannum" <root () IHACK NET>
Date: Wed, 7 Mar 2001 10:55:15 -0800
On Wed, Mar 07, 2001 at 04:26:41PM +0100, Kenny Jansson wrote:
Some stacks will allow TCP connection to be established to the broadcast address configured on any given interface. FreeBSD has had this behaviour for some time 4.x up until 2001/03/03 17:39:20 PST when a fix was comitted to RELENG_4 OpenBSD also exhibits this behaviour. (Tested on 2.7)
A few notes. Net/2 and 4.4BSD had explicit code of the form: case TCPS_LISTEN: { ... if (m->m_flags & M_BCAST) goto drop; ... This code lives on in a slightly different form in all of the systems today. It's true that this doesn't catch packets that are sent by Ethernet unicast to the IP broadcast address. I'm not sure what the prevailing opinion on this is, but we should probably filter such packets.
Current thread:
- Broadcast and multi-homed routing condition in TCP/IP stack. Kenny Jansson (Mar 07)
- Re: Broadcast and multi-homed routing condition in TCP/IP stack. Charles M. Hannum (Mar 07)