Re: [PATCH 4/8] rfkill: introduce RFKILL_STATE_MAX

[Ivo van Doorn <ivdoorn@gmail.com>]

On Saturday 02 August 2008, Henrique de Moraes Holschuh wrote:
> While it is interesting to not add last-enum-markers because it allows gcc
> to warn us of switch() statements missing a valid state, we really should
> be handling memory corruption on a rfkill state with default clauses,
> anyway.
> 
> So add RFKILL_STATE_MAX and use it where applicable.  It makes for safer
> code in the long run.
> 
> Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
> Cc: Ivo van Doorn <IvDoorn@gmail.com>

Acked-by: Ivo van Doorn <IvDoorn@gmail.com>

> ---
>  include/linux/rfkill.h |    1 +
>  net/rfkill/rfkill.c    |   11 ++++++++---
>  2 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/rfkill.h b/include/linux/rfkill.h
> index e92d8e9..4cd64b0 100644
> --- a/include/linux/rfkill.h
> +++ b/include/linux/rfkill.h
> @@ -49,6 +49,7 @@ enum rfkill_state {
>  	RFKILL_STATE_SOFT_BLOCKED = 0,	/* Radio output blocked */
>  	RFKILL_STATE_UNBLOCKED    = 1,	/* Radio output allowed */
>  	RFKILL_STATE_HARD_BLOCKED = 2,	/* Output blocked, non-overrideable */
> +	RFKILL_STATE_MAX,		/* marker for last valid state */
>  };
>  
>  /*
> diff --git a/net/rfkill/rfkill.c b/net/rfkill/rfkill.c
> index 5320210..ea872e5 100644
> --- a/net/rfkill/rfkill.c
> +++ b/net/rfkill/rfkill.c
> @@ -201,6 +201,8 @@ static int rfkill_toggle_radio(struct rfkill *rfkill,
>  		 * BLOCK even a transmitter that is already in state
>  		 * RFKILL_STATE_HARD_BLOCKED */
>  		break;
> +	default:
> +		return -EINVAL;
>  	}
>  
>  	if (force || state != rfkill->state) {
> @@ -234,6 +236,9 @@ static void __rfkill_switch_all(const enum rfkill_type type,
>  {
>  	struct rfkill *rfkill;
>  
> +	if (unlikely(state >= RFKILL_STATE_MAX))
> +		return;
> +
>  	rfkill_global_states[type].current_state = state;
>  	list_for_each_entry(rfkill, &rfkill_list, node) {
>  		if ((!rfkill->user_claim) && (rfkill->type == type)) {
> @@ -329,9 +334,7 @@ int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state)
>  {
>  	enum rfkill_state oldstate;
>  
> -	if (state != RFKILL_STATE_SOFT_BLOCKED &&
> -	    state != RFKILL_STATE_UNBLOCKED &&
> -	    state != RFKILL_STATE_HARD_BLOCKED)
> +	if (unlikely(state >= RFKILL_STATE_MAX))
>  		return -EINVAL;
>  
>  	mutex_lock(&rfkill->mutex);
> @@ -735,6 +738,8 @@ int __must_check rfkill_register(struct rfkill *rfkill)
>  		return -EINVAL;
>  	if (rfkill->type >= RFKILL_TYPE_MAX)
>  		return -EINVAL;
> +	if (rfkill->state >= RFKILL_STATE_MAX)
> +		return -EINVAL;
>  
>  	snprintf(dev->bus_id, sizeof(dev->bus_id),
>  		 "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);