Input: leds - fix out of bound access

UI_SET_LEDBIT ioctl() causes the following KASAN splat when used with
led > LED_CHARGING:

[ 1274.663418] BUG: KASAN: slab-out-of-bounds in input_leds_connect+0x611/0x730 [input_leds]
[ 1274.663426] Write of size 8 at addr ffff88003377b2c0 by task ckb-next-daemon/5128

This happens because we were writing to the led structure before making
sure that it exists.

Reported-by: Tasos Sahanidis <tasos@tasossah.com>
Tested-by: Tasos Sahanidis <tasos@tasossah.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/input/input-leds.c b/drivers/input/input-leds.c
index 766bf2660116..5f04b2d94635 100644
--- a/drivers/input/input-leds.c
+++ b/drivers/input/input-leds.c
@@ -88,6 +88,7 @@ static int input_leds_connect(struct input_handler *handler,
                               const struct input_device_id *id)
 {
         struct input_leds *leds;
+        struct input_led *led;
         unsigned int num_leds;
         unsigned int led_code;
         int led_no;
@@ -119,14 +120,13 @@ static int input_leds_connect(struct input_handler *handler,
 
         led_no = 0;
         for_each_set_bit(led_code, dev->ledbit, LED_CNT) {
-                struct input_led *led = &leds->leds[led_no];
+                if (!input_led_info[led_code].name)
+                        continue;
 
+                led = &leds->leds[led_no];
                 led->handle = &leds->handle;
                 led->code = led_code;
 
-                if (!input_led_info[led_code].name)
-                        continue;
-
                 led->cdev.name = kasprintf(GFP_KERNEL, "%s::%s",
                                            dev_name(&dev->dev),
                                            input_led_info[led_code].name);