Prevent buffer overrun accessing btn_labels

We go up to BTN_JOYSTICK, hence group can have a value of up to including 15.
The actual btn_labels only has 6 elements though.

Found by coverity.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/evdev.c b/src/evdev.c
index 0fcb0bb..2c88343 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -2790,6 +2790,9 @@ static void EvdevInitButtonLabels(EvdevPtr pEvdev, int natoms, Atom *atoms)
         int group = (button % 0x100)/16;
         int idx = button - ((button/16) * 16);
 
+        if (group >= ArrayLength(btn_labels))
+            break;
+
         if (!libevdev_has_event_code(pEvdev->dev, EV_KEY, button))
             continue;