Wireshark-dev: Re: [Wireshark-dev] pcapng options

From: Jasper Bongertz <jasper.bongertz@xxxxxxxx>
Date: Fri, 02 Nov 2012 14:17:20 +0100
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On 02.11.2012 04:23, Guy Harris wrote:

>> Is it legal to have a pcap-ng file that contains a block with
>> options that does not contain an opt_endofopt option?
> 
> My inclination would be to say "yes", to indicate that option
> processing must stop when you reach the end of the block even if no
> opt_endofopt option is seen, but also indicate that option
> processing should stop when an opt_endofopt block is seen, even if
> there is more data remaining in the block.  So my inclination would
> be to say:
> 
> option processing MUST stop when you run out of data in the block;
> 
> option processing MUST stop when you see an opt_endofopt block;
> 
> option lists that contain at least one non-opt_endofopt option
> SHOULD also have an opt_endofopt option at the end;
> 
> and possibly change the last SHOULD to MUST in order not to upset
> code that *doesn't* check for the end of the block, even if that
> code is insecure.

I agree. The opt_endofopt is a nice-to-have in my eyes, because - as
Guy said - you need to check that your code is not running past the
end of a block anyway, and that requires keeping track of where you are.

I think we can go for a "MUST" on the last one as well; code that
reads pcap-ng still has to expect that there is no opt_endofopt
because of the first rule.
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