Ethereal-dev: [Ethereal-dev] Re: ASN.1 File Dissection

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From: Graeme Lunt <graeme.lunt@xxxxxxxxx>
Date: Fri, 11 Nov 2005 08:05:56 +0100
Hi,

Is this proposed patch still under review, or has it been missed or rejected?

If the latter, any feedback?

Thanks,

Graeme

> There are a number of circumstances when it useful to dissect an ASN.1 BER
> encoded file.
> For example, a X.509 certificate, a PKCS#12 file or a lump of X.400 content
> from an MTA queue.
>
> So attached is patch for an ASN.1 BER capture file format.
>
> Briefly,
>
> * a file is determined to ASN.1 if
>        i) the first Tag is constructed and either a SET, SEQUENCE or
> CONTEXT [<32]
>        ii) the associated Length matches the length of the file
>        (This algorithm may need to be tweaked.)
>
> * there is obviously only one "frame" which reflects the content of the file
>
>  - the arrival time of the frame reflects the time on the file.
>
> * dissect_unknown_ber() has been significantly upgraded to handle arbitary
> ASN.1
>
> * a heuristic based on the OIDs found in the ASN.1 has been added to see if
> a better
>  dissection can be made. For example, if id-signedData is found, the ASN.1
> can be
>  dissected as CMS.
>
> * the above heuristic can be turned off through a preference if it is making
> the wrong
>  decision.
>
> The patch also includes a BER preference to allow the user to specify a file
> that
> contains OID information for OIDs that Ethereal hasn't already encoded.
>
> This is my first venture outside of dissectors, so let me know if I haven't
> covered all the
> bases for a new capture file format.
>
> Graeme
>
>
>