Re: UDP recvmsg blocks after select(), 2.6 bug?

Colin Phipps
2004-10-09T12:06:27Z

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>