Wireshark · Wireshark-dev: Re: [Wireshark-dev] how to handle dissecting length encoded strings

[Jakub Zawadzki <darkjames@xxxxxxxxxxxxxxxx>]

On Mon, Mar 14, 2011 at 09:51:06AM -0400, Fulko Hew wrote:
> I'm looking into a bug in a dissector, and I don't see what the 'right
> way' to fix it would be.
> Here's the existing code snippet:
> 
> static int
> dissect_octet_string(tvbuff_t *tvb, proto_tree *tree, int offset, char flags)
> {
>     guint32 n_oct, p_noct;
>     char context[1024];
> 
>     NORLEL(flags, n_oct, tvb, offset);
> 
>     p_noct = PADDING(n_oct);
>     if (n_oct >= 1024)
>         THROW(ReportedBoundsError);
>     if (n_oct > 0)
>         count = tvb_get_nstringz(tvb, offset + 4, n_oct, context);
>     context[n_oct]='\0';
> 
>     proto_tree_add_uint(tree, hf_ostring_len, tvb, offset, 4, n_oct);
>     proto_tree_add_string(tree, hf_ostring, tvb, offset + 4, n_oct, context);
>     return p_noct + 4;
> }
> 
> Comments anyone?

hf of type FT_UINT_STRING wouldn't work for you?

FT_UINT_STRING      
	A counted string of characters, consisting
	of a count (represented as an integral value,
	of width given in the proto_tree_add_item()
	call) followed immediately by that number of
	characters

Cheers.