[PATCH 3.16 050/212] USB: serial: ssu100: fix control-message error handling

From: Ben Hutchings
Date: Thu Jun 01 2017 - 12:36:27 EST


3.16.44-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

commit 1eac5c244f705182d1552a53e2f74e2775ed95d6 upstream.

Make sure to detect short control-message transfers rather than continue
with zero-initialised data when retrieving modem status and during
device initialisation.

Fixes: 52af95459939 ("USB: add USB serial ssu100 driver")
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/usb/serial/ssu100.c | 31 ++++++++++++++++++++++++-------
1 file changed, 24 insertions(+), 7 deletions(-)

--- a/drivers/usb/serial/ssu100.c
+++ b/drivers/usb/serial/ssu100.c
@@ -80,9 +80,17 @@ static inline int ssu100_setdevice(struc

static inline int ssu100_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, 300);
+ int ret;
+
+ ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+ QT_SET_GET_DEVICE, 0xc0, 0, 0,
+ data, 3, 300);
+ if (ret < 3) {
+ if (ret >= 0)
+ ret = -EIO;
+ }
+
+ return ret;
}

static inline int ssu100_getregister(struct usb_device *dev,
@@ -90,10 +98,17 @@ static inline int ssu100_getregister(str
unsigned short reg,
u8 *data)
{
- return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
- QT_SET_GET_REGISTER, 0xc0, reg,
- uart, data, sizeof(*data), 300);
+ int ret;

+ ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+ QT_SET_GET_REGISTER, 0xc0, reg,
+ uart, data, sizeof(*data), 300);
+ if (ret < sizeof(*data)) {
+ if (ret >= 0)
+ ret = -EIO;
+ }
+
+ return ret;
}


@@ -289,8 +304,10 @@ static int ssu100_open(struct tty_struct
QT_OPEN_CLOSE_CHANNEL,
QT_TRANSFER_IN, 0x01,
0, data, 2, 300);
- if (result < 0) {
+ if (result < 2) {
dev_dbg(&port->dev, "%s - open failed %i\n", __func__, result);
+ if (result >= 0)
+ result = -EIO;
kfree(data);
return result;
}