Input: leds - fix out of bound access

BugLink: http://bugs.launchpad.net/bugs/1778759
commit 6bd6ae639683c0b41f46990d5c64ff9fbfa019dc upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/input/input-leds.c b/drivers/input/input-leds.c
index 766bf26601163c37aebf265160b4d3d0ce09617f..5f04b2d946350d2ef29d579d6e002da061d93ce0 100644 (file)
--- 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);