Date: Fri, 21 Jan 2000 15:11:06 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Alfred Perlstein <bright@wintelcom.net> Cc: Brett Glass <brett@lariat.org>, security@FreeBSD.ORG Subject: Re: stream.c worst-case kernel paths Message-ID: <200001212311.PAA64559@apollo.backplane.com> References: <4.2.2.20000120182425.01886ec0@localhost> <20000120195257.G14030@fw.wintelcom.net>
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:It's a pretty good analysis, besideds the improvements mentioned
:here i _really_ think we should be able to delay the checksum as
:far as possible, I've been playing with this for a bit and I'll
:see how far it can be safely moved.
:
:Doing a checksum on an invalid packet is not worth it, might as
:well take the packet at face value, allow it to drop out, and
:only when it's about to be accepted _finally_ take the hit and do
:the checksum.
:
:As far as limiting RST and ICMP I really believe it's time that
:such things are _on_ by default.
:
:-Alfred
No, this is far too dangerous. If a packet is bad due to being
corrupted then you want to throw it away (via the checksum check)
*BEFORE* you start messing around with the socket state. Otherwise
a perfectly legitimate packet that got corrupted in transit may
cause a disconnect or other failure.
-Matt
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