[PATCH] media: uvcvideo: Fix buffer overflow in uvc_mapping_get_menu_value()

[Dan Carpenter <error27@gmail.com>]

The "idx" value is a user controlled u32 so we have to bounds check it
before calling test_bit() to avoid reading beyond the end of the bitmap.

Fixes: 4e15c535659b ("media: uvcvideo: Support any size for mapping get/set")
Signed-off-by: Dan Carpenter <error27@gmail.com>
---
 drivers/media/usb/uvc/uvc_ctrl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 3ca108b83f1d..f157ed99be4e 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -538,7 +538,7 @@ static void uvc_mapping_set_s32(struct uvc_control_mapping *mapping,
 static int uvc_mapping_get_menu_value(const struct uvc_control_mapping *mapping,
 				      u32 idx)
 {
-	if (!test_bit(idx, &mapping->menu_mask))
+	if (idx >= BITS_PER_LONG || !test_bit(idx, &mapping->menu_mask))
 		return -EINVAL;
 
 	if (mapping->menu_mapping)
-- 
2.53.0