From e17c48c3280e70dc5c8a9d579613ea732591dedf Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 12 Jan 2017 14:56:20 +0100 Subject: [PATCH] USB: serial: quatech2: fix control-message error handling commit 8c34cb8ddfe808d557b51da983ff10c02793beb2 upstream. Make sure to detect short control-message transfers when fetching modem and line state in open and when retrieving registers. This specifically makes sure that an errno is returned to user space on errors in TIOCMGET instead of a zero bitmask. Also drop the unused getdevice function which also lacked appropriate error handling. Fixes: f7a33e608d9a ("USB: serial: add quatech2 usb to serial driver") Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/quatech2.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c index bd1a1307e0f0..1d17779b2203 100644 --- a/drivers/usb/serial/quatech2.c +++ b/drivers/usb/serial/quatech2.c @@ -188,22 +188,22 @@ static inline int qt2_setdevice(struct usb_device *dev, u8 *data) } -static inline int qt2_getdevice(struct usb_device *dev, u8 *data) -{ - return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), - QT_SET_GET_DEVICE, 0xc0, 0, 0, - data, 3, QT2_USB_TIMEOUT); -} - static inline int qt2_getregister(struct usb_device *dev, u8 uart, u8 reg, u8 *data) { - return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), - QT_SET_GET_REGISTER, 0xc0, reg, - uart, data, sizeof(*data), QT2_USB_TIMEOUT); + int ret; + ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), + QT_SET_GET_REGISTER, 0xc0, reg, + uart, data, sizeof(*data), QT2_USB_TIMEOUT); + if (ret < sizeof(*data)) { + if (ret >= 0) + ret = -EIO; + } + + return ret; } static inline int qt2_setregister(struct usb_device *dev, @@ -372,9 +372,11 @@ static int qt2_open(struct tty_struct *tty, struct usb_serial_port *port) 0xc0, 0, device_port, data, 2, QT2_USB_TIMEOUT); - if (status < 0) { + if (status < 2) { dev_err(&port->dev, "%s - open port failed %i\n", __func__, status); + if (status >= 0) + status = -EIO; kfree(data); return status; }