Ethereal-users: [Ethereal-users] [Patch] Bug in RCMP dissector (was RE: "Malformed" ASF RMCP ACK
Hi,
Please find attached a patch for the RMCP dissector that will make it not
to look for data blocks in ACK packets, plus a sample capture with packets
that now appear as malformed because they lack it. The protocol specification
is referred to below.
Regards,
Francisco
> -----Original Message-----
> From: ethereal-users-bounces@xxxxxxxxxxxx
> [mailto:ethereal-users-bounces@xxxxxxxxxxxx]
> Sent: miércoles, 02 de marzo de 2005 22:29
> To: 'Ethereal user support'
> Subject: RE: [Ethereal-users] RE: "Malformed" ASF RMCP ACK packets
>
>
> > Hi,
> >
> > > Re-sending due to lack of acknowledgement/response:
> > >
> > > Ethereal (v0.10.4) is reporting received ASF RMCP ACK packets
> > > as being "malformed" when they appear to be perfectly
> > valid. Example:
> > >
> > > 0000 00 0f 1f d7 cd 46 00 b0 d0 21 00 48 08 00 45 00
> > > 0010 00 20 3d 9a 00 00 20 11 fd 44 ac 10 01 ef ac 10
> > > 0020 05 df 02 6f 02 6e 00 0c 93 84 06 00 01 86 00 00
> > > 0030 00 00 00 00 00 00 00 00 00 00 00 00
> > >
> > > This is an ASF RMCP ACK of an ASF RMCP Capabilities
> Request packet.
> > >
> > > I can only guess that Ethereal is assuming that ASF RMCP ACK
> > > packets are supposed to include a data block, when in fact
> > they do not
> > > (see section 3.2.2.1 Note 1 in the ASF Specification).
> > >
> > > Perhaps someone on the Ethereal development team can point
> > > out exactly what it is that Ethereal is expecting, but not
> > finding, in
> > > this packet?
> >
> > There is a development list you might use if you are trying
> > specifically to contact developers -althouth I believe most
> > of them subscribe to this also-.
> >
> > I suppose nobody can immediately derive your problem from
> > your description, so if you attach a trace -the trace file
> > with the packet, not only the hex dump- I can try and have a
> > look at it; with the disclaimer that I don't know a bit
> > about ASF, I can only try and find the place where the
> > program is expecting
> > something it does not find. If you add a pointer to the ASF
> > Specification it would probably also help.
>
> I attached a trace file that demonstrates this problem (a
> valid RMCP ack packet reported as "malformed" by Ethereal).
>
> Here's a link to the ASF specification:
>
> http://www.dmtf.org/standards/documents/ASF/DSP0136.pdf
>
> -Rob
>
Attachment:
bad_rmcp_ack
Description: Binary data
Attachment:
packet-rmcp.patch
Description: Binary data
