Date: Sat, 9 Oct 2004 13:07:50 +0100
From: Colin Phipps <cph@cph.demon.co.uk>
To: linux-kernel@vger.kernel.org
Subject: Re: UDP recvmsg blocks after select(), 2.6 bug?
Message-ID: <20041009120750.GA1948@cph.demon.co.uk>
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So the performance gain is significant. And programs that break were
buggy anyway. But that still leaves the question of whether it benefits
users, given that there is a lot of software, buggy by this
interpretation, that can break. In particular, exposing UDP daemons to
denial of service using bad-checksum UDP packets looks like a rather
interesting security issue.

I have just tried syslog and inetd on a couple of machines running
2.6.8.1, and both hang when given a single bad-checksum udp packet.
hping2 -2 -c 1 -b is the tool of choice.  Sure, they could have broken
anyway, but this makes them easy targets - and presumably they are the
tip of the iceberg.

-- 
Colin Phipps <cph@cph.demon.co.uk>
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