Hi all,
I've been using ethereal for a little while now (since about v0.8.12, now
on v0.18.14.1) on NT (v4,SP5) with winpcap (v2.02) and found it very
helpful for network traffic analysis, however I've come across a problem
I'd like others' thoughts (ie help) on.
Whilst doing some traffic captures on a network the other day I had
ethereal in capture mode, and it GPF'd (Exception number: c0000005 (access
violation)), which had never happened before..... after some fiddling
around it became apparent that the crash was happening when ethereal tried
to decode some part of what it had captured, so I ran some captures using
tethereal for later reference and left the site.
Back in the office, I ran ethereal on the captures and reliably reproduced
the GPF's - some captures did and some didnt but always the same ones.
I ran a 'tethereal -t ad -r capfile > caplist.txt' on one of the captures
that gpf'd under ethereal and it completed listing the summary details of
all packets in the dump, without crashing, but a 'tethereal -V -x -t ad -r
capfile > longcaplist.txt' gpf'd as well, and the output was truncated near
the end of frame 13096.
After some fiddling with editcap and tethereal's, I've found that frame
13097 in the dump file will reliably GPF ethereal and tethereal.
(there may well be others later in the dump - havnt got that far yet)
The short summary of the packet is that its a 'SMBgetatr Response', but
there are lots of others of the same type in the capture file before it
that decode OK.
If I run a decode on just that packet with tethereal -V -x there is nothing
output before it GPF's....
I'm guessing that something in the packet is causing the decoder to die,
but the question is whether its a bug in the decoder or theres really some
foul data been running on the wire.... either way I need some way of
getting more detailed info on whats up....
Whats the next step? are there some other tools for working out whats wrong
with this dump/capture? is there any debug options in ethereal I could turn
on?
The packet in question is available for testing if someone wants to have a
go at it - its only 153 bytes long.
regards,
Michael Hennessy
------------------------------------------------------------------------
----------
Excalibur Engineering Pty. Ltd.
Mobile Phone No : (+61) 0411 789392
Office Phone No. : (+61) 0249 400133
Office Fax No. : (+61) 0249 400266
Email Address : hennessy@xxxxxxxxxxxxxxxx
Postal Address : PO Box 1088 Newcastle NSW 2300, Australia
Street Address : 80 Chin Chen Street, Islington,
Newcastle, 2296, Australia
------------------------------------------------------------------------
----------