patch "USB: serial: ftdi_sio: fix modem-status error handling" added to usb-testing

This is a note to let you know that I've just added the patch titled

USB: serial: ftdi_sio: fix modem-status error handling

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the usb-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From: Johan Hovold <[email protected]>
Date: Thu, 12 Jan 2017 14:56:11 +0100
Subject: USB: serial: ftdi_sio: fix modem-status error handling

Make sure to detect short responses when fetching the modem status in order to avoid parsing uninitialised buffer data and having bits of it leak to user space.

Note that we still allow for short 1-byte responses.

---
 drivers/usb/serial/ftdi_sio.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

index 23d14b98ae2a..6dee20fc7e45 100644
@@ -2428,8 +2428,12 @@ static int ftdi_get_modem_status(struct usb_serial_port *port,
 			FTDI_SIO_GET_MODEM_STATUS_REQUEST_TYPE,
 			0, priv->interface,
 			buf, len, WDR_TIMEOUT);
-	if (ret < 0) {
+
+	/* NOTE: We allow short responses and handle that below. */
+	if (ret < 1) {
 		dev_err(&port->dev, "failed to get modem status: %d\n", ret);
+		if (ret >= 0)
+			ret = -EIO;
 		ret = usb_translate_errors(ret);
 		goto out;
 	}

2.11.1