From owner-freebsd-security  Fri Jan 21 20:39:59 2000
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From: gdonl@tsc.tdk.com (Don Lewis)
Date: Fri, 21 Jan 2000 20:39:26 -0800
In-Reply-To: Matthew Dillon <dillon@apollo.backplane.com>
       "Re: stream.c worst-case kernel paths" (Jan 21,  7:59pm)
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To: Matthew Dillon <dillon@apollo.backplane.com>,
	Giorgos Keramidas <charon@hades.hell.gr>
Subject: Re: stream.c worst-case kernel paths
Cc: Brett Glass <brett@lariat.org>, Warner Losh <imp@village.org>,
	Darren Reed <avalon@coombs.anu.edu.au>, security@FreeBSD.ORG
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On Jan 21,  7:59pm, Matthew Dillon wrote:
} Subject: Re: stream.c worst-case kernel paths
} :So what needs to be done is:
} :
} :(a) drop all multicast packets that reach the tcp stack.
} :(b) extend ICMP_BANDLIM to RST packets, and
} :(c) avoid sending anything tcp to a multicast address
} :
} :Do I forget something here?
} :
} :-- Giorgos
} 
}     That's pretty much it.  I've already sent a patch set to Warner for (b).
}     I don't think we should do (a) or (c) until after the release, multicast
}     isn't going to explode on us in the next 4 months.

But that doesn't stop an attacker from sending forged TCP packets with
forged multicast addresses.  Spraying the local network with a multicast
response to an incoming unicast seems like a bad idea.


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