Date: Thu, 20 Jan 2000 21:27:16 -0700 From: Brett Glass <brett@lariat.org> To: Darren Reed <avalon@coombs.anu.edu.au> Cc: security@FreeBSD.ORG Subject: Re: stream.c worst-case kernel paths Message-ID: <4.2.2.20000120212336.01882220@localhost> In-Reply-To: <200001210417.PAA24853@cairo.anu.edu.au> References: <4.2.2.20000120182425.01886ec0@localhost>
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At 09:17 PM 1/20/2000 , Darren Reed wrote: >Also, what about the simultaneous connection problem ? (both ends send >SYN's to the other, same ports). The odds of the source ports being the same are minuscule. Wouldn't this prevent a problem? Or am I misunderstanding the implications here? > Normally, we'll wind up at the label "dropwithreset", which means we'll > > send back a RST. This suggests that restricting RSTs will help with the > > DoS. (Does anyone know if not sending an RST violates any RFCs if there > > was never a connection?) > >Yes. RFC 793, figure 11, page 35, describes the prescribed behaviour. Isn't there a later RFC describing techniques for avoiding DoSes? (If not, it may be time to write one. "Best practice" is changing now that the 'Net is getting to be a hostile place.) --Brett To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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