[PATCH v2] media: uvcvideo: Add sanity check to uvc_mapping_get_menu_value()

[Dan Carpenter <error27@gmail.com>]

Smatch warned that "idx" could be too large, leading to an out of bounds
read.  When we reviewed the callers it was a false positive.  However,
add a sanity check here anyway, just for future proofing and being
consistent with the rest of the code.

Signed-off-by: Dan Carpenter <error27@gmail.com>
---
v2: It's not a real bug but Ricardo asked me to add the sanity check
anyway.  Use BITS_PER_TYPE() instead of BITS_PER_LONG.

 drivers/media/usb/uvc/uvc_ctrl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index d2f722bc3459..249c68783474 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -538,7 +538,8 @@ 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_TYPE(mapping->menu_mask) ||
+	    !test_bit(idx, &mapping->menu_mask))
 		return -EINVAL;
 
 	if (mapping->menu_mapping)
-- 
2.53.0