Re: [PATCH wpan-tools] mac: range checking for command accepting only 0 or 1

[Alexander Aring <alex.aring@gmail.com>]

Hi Stefan,

On Wed, Aug 19, 2015 at 04:13:24PM +0200, Stefan Schmidt wrote:
> lbt and ackreq_default only accept 0or 1 as arguments which we did not
> acount for so far. Testing invalid arguments and checking teh return
> code uncovered this one.
> 
> Signed-off-by: Stefan Schmidt <stefan@osg.samsung.com>
> ---
>  src/mac.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/src/mac.c b/src/mac.c
> index 76db58f..26c6fc5 100644
> --- a/src/mac.c
> +++ b/src/mac.c
> @@ -175,6 +175,8 @@ static int handle_lbt_mode(struct nl802154_state *state,
>  	mode = strtoul(argv[0], &end, 0);
>  	if (*end != '\0')
>  		return 1;
> +	if (mode != 0 && mode != 1)
> +		return 1;
>  
>  	NLA_PUT_U8(msg, NL802154_ATTR_LBT_MODE, mode);
>  
> @@ -202,6 +204,8 @@ static int handle_ackreq_default(struct nl802154_state *state,
>  	ackreq = strtoul(argv[0], &end, 0);
>  	if (*end != '\0')
>  		return 1;
> +	if (ackreq != 0 && ackreq != 1)
> +		return 1;
>  

range checks should be handled by kernelspace. Currently we do a "!!var"
conversion there. Maybe we should change it there and accept "1" or "0".

We should never handle "if a range is valid or not" inside userspace,
otherwise other applications which talking to nl802154 can do a
different handling then.

- Alex