[PATCH 2/2] [media] v4l2-ctrls: fix integer overflow in try_set_ext_ctrls()

[Xi Wang <xi.wang@gmail.com>]

A large cs->count from userspace may overflow the allocation size,
leading to memory corruption.  try_set_ext_ctrls() can be reached
from subdev_do_ioctl() or __video_do_ioctl().

Use kmalloc_array() to avoid the overflow.

Signed-off-by: Xi Wang <xi.wang@gmail.com>
---
 drivers/media/video/v4l2-ctrls.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c
index f355fd5..6f38a5d 100644
--- a/drivers/media/video/v4l2-ctrls.c
+++ b/drivers/media/video/v4l2-ctrls.c
@@ -2219,7 +2219,8 @@ static int try_set_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
 		return class_check(hdl, cs->ctrl_class);
 
 	if (cs->count > ARRAY_SIZE(helper)) {
-		helpers = kmalloc(sizeof(helper[0]) * cs->count, GFP_KERNEL);
+		helpers = kmalloc_array(cs->count, sizeof(helper[0]),
+					GFP_KERNEL);
 		if (!helpers)
 			return -ENOMEM;
 	}
-- 
1.7.5.4