From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pablo Neira Ayuso <pablo@netfilter.org>
Subject: Re: [ebtables-compat-experimental5 PATCH] iptables: xtables-eb:
 adjust policy in user-defined chains
Date: Wed, 19 Nov 2014 13:36:04 +0100
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To: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
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On Wed, Nov 19, 2014 at 01:23:01PM +0100, Arturo Borrero Gonzalez wrote:
> On 18 November 2014 19:43, Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> >>                       if (command == 'N' && c == 'P') {
> >> -                             command = c;
> >> -                             optind--; /* No table specified */
> >> -                             goto handle_P;
> >> +                             xtables_error(PARAMETER_PROBLEM,
> >> +                                           "The default policy in user-defined"
> >> +                                           " chains is RETURN (mandatory)");
> >>                       }
> >
> > I'd really prefer to avoid changes in the ebtables parser. Could you
> > perform this checking from later on, when validating the
> > configuration.
> >
> >         if (strcmp(chain, "INPUT") != 0 &&
> >             strcmp(chain, "FORWARD") != 0 &&
> >             ...                           &&
> >             strcmp(policy, "RETURN") != 0)
> >                 xtables_error("...);
> >
> 
> In the user-defined chain creation path, the code jumps to several
> places (the goto handle_P; thing). I don't see clearly a zone where to
> put these validations.
> 
> Could you please point to where would you like to put this code?

This will leave the while ((c = getopt_long ...) loop at some point,
right? So perform the validation after the parsing is done.