media: cros-ec-cec: limit msg.len to CEC_MAX_MSG_SIZE

[ Upstream commit 2dc73b4866 ]

I expect that the hardware will have limited this to 16, but just in
case it hasn't, check for this corner case.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/media/cec/platform/cros-ec/cros-ec-cec.c

@@ -44,6 +44,8 @@ static void handle_cec_message(struct cros_ec_cec *cros_ec_cec)
 	uint8_t *cec_message = cros_ec->event_data.data.cec_message;
 	unsigned int len = cros_ec->event_size;
 
+	if (len > CEC_MAX_MSG_SIZE)
+		len = CEC_MAX_MSG_SIZE;
 	cros_ec_cec->rx_msg.len = len;
 	memcpy(cros_ec_cec->rx_msg.msg, cec_message, len);