Wireshark · Ethereal-dev: Re: [ethereal-dev] SNMP Bug Report

[Guy Harris <gharris@xxxxxxxxxxxx>]

On Sun, Jun 25, 2000 at 01:51:20PM -0700, Guy Harris wrote:
> Unfortunately, "sprint_value()" does no length checking, and there's no
> way to figure out how much space it will need, so the only place where
> the variable *could* be variable-length is the code that formats it if
> it's binary; I don't know whether it's worth having *two* variables, a
> fixed-length buffer into which "format_value()" formats the string and
> a pointer to a dynamically-allocated string buffer into which binary
> values are dumped, or not.

It's definitely not worth having *two* variables, because

	1) if the SNMP dissector is linked with "-lsnmp", all the calls
	   that use "vb_display_string" are calls to "format_value()",
	   so it *has* to be a fixed-length string, and no bounds
	   checking can be done on it;

	2) if it's not linked with "-lsnmp", all the code that uses it
	   can use a dynamically-allocated buffer.

It is probably worth dynamically allocating the buffer in the case where
it's not linked with "-lsnmp"; however, *all* we can do when it's linked
with "-lsnmp" is to make the fixed-length buffer longer.