Ethereal-dev: [Ethereal-dev] Re: Asn.1 and indefinite length.
The handling of indefinite length is very incomplete in packet-ber.
Mainly due to that indefinite length encodings are very uncommon in
those protocols that mainly use packet-ber.c
I would definitely be interested in refining packet-ber so that it
starts doing proper handling of indefinite length fields the correct
way but will not have time to do so in the next few weeks.
Please ping me in two weeks time and i can start looking at it.
I would also need an example capture with several indefinite lengths
in it, as your example you describe plus the ASN specification for the
protocol.
(ill then hack up a quick test asn2eth generated version of the
protocol for testing the indefinite length handling but not check in
that autogenerated protocol)
On 5/20/05, Yuriy Sidelnikov <YSidelnikov@xxxxxxxx> wrote:
> Anders Broman wrote:
> Let's say we've sequence:
>
> af - tag 1
> 80 - len1
> 72 - tag2
> 80 - len2
> ... something related to tag2
> ... something related to tag1
> 0000 - first delimeter(end of tag2)
> 0000 - second delimiter(end of tag1)
> a1 - another tags
> 8101
> 01
> a2
> 820001
> 01
> end of tvb.
>
> Both API will return wrong length, for example, for x'af' tag from x'72' to
>
> the end of tvb buffer.But correct value will be from x'72' to the second
> delimeter.
>
> Regards,
> Yuriy.
>
>
> >>Hi,
> >>analyzing some new ftam trace files I found that the indefinite length in
> >>the ASN.1 is not so rare thing as I thought.
> >>So I would like to have correct ASN.1 API.
> >>The question is that neither obsolete asn1.c nor new packet-ber.c can
> >>handle with the indefinite length in asn.1 stream.
> >>So what is the better:
> >>1.Add support for the indefinite length say "over" asn1.c.It is not very
> >>hard so we'll have working dissector pretty soon.Really I need only one
> >>thing more - to get correct length in case of the indefinite length.
> >>2.Try to use new api in the packet-ftam/acse/pres keeping in mind that
> >>somebody will be so kind to add the support for the indefinite length.
> It's
> >>not very easy way to go.
> >>
> >>Regards,
> >>Yuriy Sidelnikov
> >
> > As far as I know both packet-ber.c and the asn1.c handle at least some
> > indefinite lengths, what exactly is it you are missing?
> >
> > Best regards
> > Anders
> >
> >
> > _______________________________________________
> > Ethereal-dev mailing list
> > Ethereal-dev@xxxxxxxxxxxx
> > http://www.ethereal.com/mailman/listinfo/ethereal-dev
>
>
>
> .............................................................
>
> Программа создания веб-сайтов за два дня: http://web.sema.ru/
>
> _______________________________________________
> Ethereal-dev mailing list
> Ethereal-dev@xxxxxxxxxxxx
> http://www.ethereal.com/mailman/listinfo/ethereal-dev
>
