rfkill: do not allow userspace to override ALL RADIOS OFF

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.

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@hmh.eng.br>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/net/rfkill/rfkill.c b/net/rfkill/rfkill.c
index dd1c3f18f31d..7d07175c407f 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.