netfilter: xt_LED: add refcounts to LED target

Add reference counting to the netfilter LED target, to fix errors when
multiple rules point to the same target ("LED trigger already exists").

Signed-off-by: Adam Nielsen <a.nielsen@shikadi.net>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 63 insertions, 6 deletions

diff --git a/net/netfilter/xt_LED.c b/net/netfilter/xt_LED.c
index efcf56db23e8..bd102c77d1f0 100644
--- a/net/netfilter/xt_LED.c
+++ b/net/netfilter/xt_LED.c
@@ -31,12 +31,18 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>");
 MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match");
 
+static LIST_HEAD(xt_led_triggers);
+static DEFINE_MUTEX(xt_led_mutex);
+
 /*
  * This is declared in here (the kernel module) only, to avoid having these
  * dependencies in userspace code.  This is what xt_led_info.internal_data
  * points to.
  */
 struct xt_led_info_internal {
+        struct list_head list;
+        int refcnt;
+        char *trigger_id;
         struct led_trigger netfilter_led_trigger;
         struct timer_list timer;
 };
@@ -53,7 +59,7 @@ led_tg(struct sk_buff *skb, const struct xt_target_param *par)
          */
         if ((ledinfo->delay > 0) && ledinfo->always_blink &&
             timer_pending(&ledinternal->timer))
-                led_trigger_event(&ledinternal->netfilter_led_trigger,LED_OFF);
+                led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
 
         led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL);
 
@@ -74,12 +80,23 @@ led_tg(struct sk_buff *skb, const struct xt_target_param *par)
 
 static void led_timeout_callback(unsigned long data)
 {
-        struct xt_led_info *ledinfo = (struct xt_led_info *)data;
-        struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
+        struct xt_led_info_internal *ledinternal = (struct xt_led_info_internal *)data;
 
         led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF);
 }
 
+static struct xt_led_info_internal *led_trigger_lookup(const char *name)
+{
+        struct xt_led_info_internal *ledinternal;
+
+        list_for_each_entry(ledinternal, &xt_led_triggers, list) {
+                if (!strcmp(name, ledinternal->netfilter_led_trigger.name)) {
+                        return ledinternal;
+                }
+        }
+        return NULL;
+}
+
 static int led_tg_check(const struct xt_tgchk_param *par)
 {
         struct xt_led_info *ledinfo = par->targinfo;
@@ -91,11 +108,25 @@ static int led_tg_check(const struct xt_tgchk_param *par)
                 return -EINVAL;
         }
 
+        mutex_lock(&xt_led_mutex);
+
+        ledinternal = led_trigger_lookup(ledinfo->id);
+        if (ledinternal) {
+                ledinternal->refcnt++;
+                goto out;
+        }
+
+        err = -ENOMEM;
         ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL);
         if (!ledinternal)
-                return -ENOMEM;
+                goto exit_mutex_only;
+
+        ledinternal->trigger_id = kstrdup(ledinfo->id, GFP_KERNEL);
+        if (!ledinternal->trigger_id)
+                goto exit_internal_alloc;
 
-        ledinternal->netfilter_led_trigger.name = ledinfo->id;
+        ledinternal->refcnt = 1;
+        ledinternal->netfilter_led_trigger.name = ledinternal->trigger_id;
 
         err = led_trigger_register(&ledinternal->netfilter_led_trigger);
         if (err) {
@@ -108,13 +139,26 @@ static int led_tg_check(const struct xt_tgchk_param *par)
         /* See if we need to set up a timer */
         if (ledinfo->delay > 0)
                 setup_timer(&ledinternal->timer, led_timeout_callback,
-                            (unsigned long)ledinfo);
+                            (unsigned long)ledinternal);
+
+        list_add_tail(&ledinternal->list, &xt_led_triggers);
+
+out:
+        mutex_unlock(&xt_led_mutex);
 
         ledinfo->internal_data = ledinternal;
+
         return 0;
 
 exit_alloc:
+        kfree(ledinternal->trigger_id);
+
+exit_internal_alloc:
         kfree(ledinternal);
+
+exit_mutex_only:
+        mutex_unlock(&xt_led_mutex);
+
         return err;
 }
 
@@ -123,10 +167,23 @@ static void led_tg_destroy(const struct xt_tgdtor_param *par)
         const struct xt_led_info *ledinfo = par->targinfo;
         struct xt_led_info_internal *ledinternal = ledinfo->internal_data;
 
+        mutex_lock(&xt_led_mutex);
+
+        if (--ledinternal->refcnt) {
+                mutex_unlock(&xt_led_mutex);
+                return;
+        }
+
+        list_del(&ledinternal->list);
+
         if (ledinfo->delay > 0)
                 del_timer_sync(&ledinternal->timer);
 
         led_trigger_unregister(&ledinternal->netfilter_led_trigger);
+
+        mutex_unlock(&xt_led_mutex);
+
+        kfree(ledinternal->trigger_id);
         kfree(ledinternal);
 }