[PATCH v2] HID: betop: fix slab-out-of-bounds Write in betop_probe

["F.A.Sulaiman" <asha.16@itfac.mrt.ac.lk>]

Syzbot reported slab-out-of-bounds Write bug in hid-betopff driver.
The problem is the driver assumes the device must have an input report but
some malicious devices violate this assumption.

So this patch checks hid_device's input is non empty before it's been used.

Reported-by: syzbot+07efed3bc5a1407bd742@syzkaller.appspotmail.com
Signed-off-by: F.A. SULAIMAN <asha.16@itfac.mrt.ac.lk>
---
 drivers/hid/hid-betopff.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/hid/hid-betopff.c b/drivers/hid/hid-betopff.c
index 0790fbd3fc9a..2d62bde21413 100644
--- a/drivers/hid/hid-betopff.c
+++ b/drivers/hid/hid-betopff.c
@@ -116,6 +116,11 @@ static int betop_probe(struct hid_device *hdev, const struct hid_device_id *id)
 {
 	int ret;
 
+	if (list_empty(&hdev->inputs)) {
+		hid_err(hdev, "no inputs found\n");
+		return -ENODEV;
+	}
+
 	if (id->driver_data)
 		hdev->quirks |= HID_QUIRK_MULTI_INPUT;
 
-- 
2.17.1