Wireshark · Wireshark-dev: Re: [Wireshark-dev] pcapng, must opt_comment string be 0-terminated?

[Michael Tuexen <Michael.Tuexen@xxxxxxxxxxxxxxxxx>]

On Jan 2, 2012, at 3:53 AM, Guy Harris wrote:

> 
> On Jan 1, 2012, at 3:00 PM, Martin Kaiser wrote:
> 
>> In a pcapng file, does the string stored in an opt_comment option have
>> to be 0-terminated? I couldn't find anything explicit about this in the
>> specification. Pcapng options have a length field, therefore I'd guess
>> the 0 termination is not required. What do you think?
> 
> The Wireshark code to read pcap-NG files uses g_strndup() to make copies of the various "UTF-8 string[s]", so the strings in the file don't have to be null-terminated, and I would read the *lack* of any mention of null-termination in the spec as an indication that
I think g_strndup() is for being secure. Even if the spec requires the string to be 0 terminated, you never
know if the file you read conforms to the spec. Since the option has a length field, using g_strndup() is the way to go.
> they don't have to be null-terminated.
> 
> I'll send the spec maintainers a note asking about this, and suggesting that the spec indicate that all strings are counted (but shouldn't contain a null byte).
Hmm, I wouldn't mind if they are 0-terminiated, I even thought they are. However, it would be great
if it would be described explicitly in the spec.

Best regards
Michael
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