From owner-freebsd-security Fri Jan 21 13:35:34 2000 Delivered-To: freebsd-security@freebsd.org Received: from lariat.lariat.org (lariat.lariat.org [206.100.185.2]) by hub.freebsd.org (Postfix) with ESMTP id 161141542B for ; Fri, 21 Jan 2000 13:35:32 -0800 (PST) (envelope-from brett@lariat.org) Received: from workhorse (IDENT:ppp0.lariat.org@lariat.lariat.org [206.100.185.2]) by lariat.lariat.org (8.9.3/8.9.3) with ESMTP id OAA24085; Fri, 21 Jan 2000 14:35:19 -0700 (MST) Message-Id: <4.2.2.20000121143004.01908960@localhost> X-Sender: brett@localhost X-Mailer: QUALCOMM Windows Eudora Pro Version 4.2.2 Date: Fri, 21 Jan 2000 14:35:16 -0700 To: Jared Mauch From: Brett Glass Subject: Re: stream.c worst-case kernel paths Cc: Wes Peters , TrouBle , security@FreeBSD.ORG In-Reply-To: <20000121162059.Y30675@puck.nether.net> References: <4.2.2.20000121140941.01a68b30@localhost> <200001211415.BAA12772@cairo.anu.edu.au> <20000121.16082400@bastille.netquick.net> <3888C7D2.D82BE362@softweyr.com> <4.2.2.20000121140941.01a68b30@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-freebsd-security@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org That's what I thought. This is really pathological. Why do we allow ourselves to send a RST to a multicast address, or accept an ACK from one? Could lower layers of the stack flag the ACK as coming from a multicast address so that we can nuke it before (or as) it hits the TCP layer? I can imagine a whole potential family of exploits involving multicast addresses and TCP. --Brett At 02:20 PM 1/21/2000 , Jared Mauch wrote: > In the multicast world you only send UDP (or other types), you >do not send tcp packets out, because you can't do a three-way >handshake. > > - jared > >On Fri, Jan 21, 2000 at 02:10:23PM -0700, Brett Glass wrote: > > At 01:55 PM 1/21/2000 , Wes Peters wrote: > > > > >Be warned if you're using the exploit program: if you select random > > >addresses, it may (will) pick multicast IP addresses, which may have > > >unintended side affects on your network. Augh! > > > > Geeze. Is it even LEGAL to ACK multicast packets? > > > > --Brett > > > > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > > with "unsubscribe freebsd-security" in the body of the message > >-- >Jared Mauch | pgp key available via finger from jared@puck.nether.net >clue++; | http://puck.nether.net/~jared/ My statements are only mine. >END OF LINE | To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message