linux-kernel - Re: [PATCH 14/15] rfkill: do not allow userspace to override ALL RADIOS OFF

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Date:	Tue, 20 May 2008 12:09:06 +0200
From:	Ivo van Doorn <ivdoorn@...il.com>
To:	Henrique de Moraes Holschuh <hmh@....eng.br>
Cc:	linux-kernel@...r.kernel.org, Thomas Renninger <trenn@...e.de>,
	Dmitry Torokhov <dtor@...l.ru>
Subject: Re: [PATCH 14/15] rfkill: do not allow userspace to override ALL RADIOS OFF

On Sunday 18 May 2008, Henrique de Moraes Holschuh wrote:
> SW_RFKILL_ALL is the "emergency power-off all radios" input event.  It must
> be handled, and must always do the same thing as far as the rfkill system
> is concerned: all transmitters are to go *immediately* offline.

I don't quite agree here. The SW_RFKILL_ALL key is the one send by thinkpad-acpi,
what makes that key so special that is has to be handled differently then a key
that only controls a single radio type?

All keys should have the same rules when it is pressed, so either all keys should
force the change, or none of them should.

> For safety, do NOT allow userspace to override EV_SW SW_RFKILL_ALL OFF.  As
> long as rfkill-input is loaded, that event will *always* be processed, and
> it will *always* force all rfkill switches to disable all wireless
> transmitters, regardless of user_claim attribute or anything else.
> 
> Signed-off-by: Henrique de Moraes Holschuh <hmh@....eng.br>
> Cc: Ivo van Doorn <IvDoorn@...il.com>
> Cc: Dmitry Torokhov <dtor@...l.ru>
> ---
>  net/rfkill/rfkill-input.c |   29 ++++++++++++++---------------
>  net/rfkill/rfkill-input.h |    1 +
>  net/rfkill/rfkill.c       |   18 ++++++++++++++++++
>  3 files changed, 33 insertions(+), 15 deletions(-)
> 
> diff --git a/net/rfkill/rfkill-input.c b/net/rfkill/rfkill-input.c
> index 29c13d3..0fadeed 100644
> --- a/net/rfkill/rfkill-input.c
> +++ b/net/rfkill/rfkill-input.c
> @@ -127,21 +127,20 @@ static void rfkill_event(struct input_handle *handle, unsigned int type,
>  		switch (code) {
>  		case SW_RFKILL_ALL:
>  			/* EVERY radio type. data != 0 means radios ON */
> -			rfkill_schedule_set(&rfkill_wwan,
> -					    (data)? RFKILL_STATE_ON:
> -						    RFKILL_STATE_OFF);
> -			rfkill_schedule_set(&rfkill_wimax,
> -					    (data)? RFKILL_STATE_ON:
> -						    RFKILL_STATE_OFF);
> -			rfkill_schedule_set(&rfkill_uwb,
> -					    (data)? RFKILL_STATE_ON:
> -						    RFKILL_STATE_OFF);
> -			rfkill_schedule_set(&rfkill_bt,
> -					    (data)? RFKILL_STATE_ON:
> -						    RFKILL_STATE_OFF);
> -			rfkill_schedule_set(&rfkill_wlan,
> -					    (data)? RFKILL_STATE_ON:
> -						    RFKILL_STATE_OFF);
> +			/* handle EPO (emergency power off) through shortcut */
> +			if (data) {
> +				rfkill_schedule_set(&rfkill_wwan,
> +						    RFKILL_STATE_ON);
> +				rfkill_schedule_set(&rfkill_wimax,
> +						    RFKILL_STATE_ON);
> +				rfkill_schedule_set(&rfkill_uwb,
> +						    RFKILL_STATE_ON);
> +				rfkill_schedule_set(&rfkill_bt,
> +						    RFKILL_STATE_ON);
> +				rfkill_schedule_set(&rfkill_wlan,
> +						    RFKILL_STATE_ON);
> +			} else
> +				rfkill_epo();
>  			break;
>  		default:
>  			break;
> diff --git a/net/rfkill/rfkill-input.h b/net/rfkill/rfkill-input.h
> index 4dae500..f63d050 100644
> --- a/net/rfkill/rfkill-input.h
> +++ b/net/rfkill/rfkill-input.h
> @@ -12,5 +12,6 @@
>  #define __RFKILL_INPUT_H
>  
>  void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state);
> +void rfkill_epo(void);
>  
>  #endif /* __RFKILL_INPUT_H */
> diff --git a/net/rfkill/rfkill.c b/net/rfkill/rfkill.c
> index ba25bde..fdde692 100644
> --- a/net/rfkill/rfkill.c
> +++ b/net/rfkill/rfkill.c
> @@ -182,6 +182,24 @@ void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
>  EXPORT_SYMBOL(rfkill_switch_all);
>  
>  /**
> + * rfkill_epo - emergency power off all transmitters
> + *
> + * This kicks all rfkill devices to RFKILL_STATE_OFF, ignoring
> + * everything in its path but rfkill_mutex.
> + */
> +void rfkill_epo(void)
> +{
> +	struct rfkill *rfkill;
> +
> +	mutex_lock(&rfkill_mutex);
> +	list_for_each_entry(rfkill, &rfkill_list, node) {
> +		rfkill_toggle_radio(rfkill, RFKILL_STATE_OFF, 1);
> +	}
> +	mutex_unlock(&rfkill_mutex);
> +}
> +EXPORT_SYMBOL_GPL(rfkill_epo);
> +
> +/**
>   * rfkill_force_state - Force the internal rfkill radio state
>   * @rfkill: pointer to the rfkill class to modify.
>   * @state: the current radio state the class should be forced to.


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