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>

diff --git a/net/rfkill/rfkill-input.c b/net/rfkill/rfkill-input.c
index d285f9a..5d4c8b2 100644 (file)
--- a/net/rfkill/rfkill-input.c
+++ b/net/rfkill/rfkill-input.c
@@ -43,11 +43,26 @@ static void rfkill_task_handler(struct work_struct *work)
        mutex_unlock(&task->mutex);
 }
 
+static void rfkill_task_epo_handler(struct work_struct *work)
+{
+       rfkill_epo();
+}
+
+static DECLARE_WORK(epo_work, rfkill_task_epo_handler);
+
+static void rfkill_schedule_epo(void)
+{
+       schedule_work(&epo_work);
+}
+
 static void rfkill_schedule_set(struct rfkill_task *task,
                                enum rfkill_state desired_state)
 {
        unsigned long flags;
 
+       if (unlikely(work_pending(&epo_work)))
+               return;
+
        spin_lock_irqsave(&task->lock, flags);
 
        if (time_after(jiffies, task->last + msecs_to_jiffies(200))) {
@@ -63,6 +78,9 @@ static void rfkill_schedule_toggle(struct rfkill_task *task)
 {
        unsigned long flags;
 
+       if (unlikely(work_pending(&epo_work)))
+               return;
+
        spin_lock_irqsave(&task->lock, flags);
 
        if (time_after(jiffies, task->last + msecs_to_jiffies(200))) {
@@ -114,21 +132,20 @@ 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_schedule_epo();
                        break;
                default:
                        break;

diff --git a/net/rfkill/rfkill-input.h b/net/rfkill/rfkill-input.h
index 4dae500..f63d050 100644 (file)
--- 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 dd1c3f1..7d07175 100644 (file)
--- a/net/rfkill/rfkill.c
+++ b/net/rfkill/rfkill.c
@@ -181,6 +181,24 @@ 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.