platform/chrome: cros_ec_proto: drop BUG_ON() in cros_ec_prepare_tx()

It is overkill to crash the kernel if the given message is oversize.

Drop the BUG_ON() and return -EINVAL instead.

Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220513044143.1045728-4-tzungbi@kernel.org

Author: Tzung-Bi Shih

drivers/platform/chrome/cros_ec_proto.c

@@ -60,7 +60,8 @@ static int prepare_packet(struct cros_ec_device *ec_dev,
 	int i;
 	u8 csum = 0;
 
-	BUG_ON(msg->outsize + sizeof(*request) > ec_dev->dout_size);
+	if (msg->outsize + sizeof(*request) > ec_dev->dout_size)
+		return -EINVAL;
 
 	out = ec_dev->dout;
 	request = (struct ec_host_request *)out;
@@ -176,7 +177,9 @@ int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
 	if (ec_dev->proto_version > 2)
 		return prepare_packet(ec_dev, msg);
 
-	BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
+	if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE)
+		return -EINVAL;
+
 	out = ec_dev->dout;
 	out[0] = EC_CMD_VERSION0 + msg->version;
 	out[1] = msg->command;