Re: [PATCH iptables] extensions: libebt_stp: fix range checking

[Phil Sutter <phil@nwl.cc>]

Hi Florian,

On Tue, Jan 23, 2024 at 05:49:33PM +0100, Florian Westphal wrote:
> This has to either consider ->nvals > 1 or check the values
> post-no-range-fixup:
> 
> ./iptables-test.py  extensions/libebt_stp.t
> extensions/libebt_stp.t: ERROR: line 12 (cannot load: ebtables -A INPUT --stp-root-cost 1)
> 
> (it tests 0 < 1 and fails, but test should be 1 < 1).
> 
> Fixes: dc6efcfeac38 ("extensions: libebt_stp: Use guided option parser")
> Signed-off-by: Florian Westphal <fw@strlen.de>
> ---
>  extensions/libebt_stp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/extensions/libebt_stp.c b/extensions/libebt_stp.c
> index 81054b26c1f0..371fa04c870f 100644
> --- a/extensions/libebt_stp.c
> +++ b/extensions/libebt_stp.c
> @@ -142,7 +142,7 @@ static void brstp_parse(struct xt_option_call *cb)
>  #define RANGE_ASSIGN(name, fname, val) {				    \
>  		stpinfo->config.fname##l = val[0];			    \
>  		stpinfo->config.fname##u = cb->nvals > 1 ? val[1] : val[0]; \
> -		if (val[1] < val[0])					    \
> +		if (stpinfo->config.fname##u < stpinfo->config.fname##l)    \
>  			xtables_error(PARAMETER_PROBLEM,		    \
>  				      "Bad --stp-" name " range");	    \
>  }

This is odd: xtopt_parse_mint() assigns UINT32_MAX to val[1] for
XTTYPE_UINT32RC if no upper end is given. Also, extensions/libebt_stp.t
passes for me. What's missing on my end?

Cheers, Phil