USB: serial: ark3116: fix register-accessor error handling
The current implementation failed to detect short transfers, something
which could lead to bits of the uninitialised heap transfer buffer
leaking to user space.
Fixes: 149fc791a452 ("USB: ark3116: Setup some basic infrastructure for
new ark3116 driver.")
Fixes: f4c1e8d597d1 ("USB: ark3116: Make existing functions 16450-aware
and add close and release functions.")
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
diff --git a/drivers/usb/serial/ark3116.c b/drivers/usb/serial/ark3116.c
index 1532cde..7812052 100644
--- a/drivers/usb/serial/ark3116.c
+++ b/drivers/usb/serial/ark3116.c
@@ -99,10 +99,17 @@ static int ark3116_read_reg(struct usb_serial *serial,
usb_rcvctrlpipe(serial->dev, 0),
0xfe, 0xc0, 0, reg,
buf, 1, ARK_TIMEOUT);
- if (result < 0)
+ if (result < 1) {
+ dev_err(&serial->interface->dev,
+ "failed to read register %u: %d\n",
+ reg, result);
+ if (result >= 0)
+ result = -EIO;
+
return result;
- else
- return buf[0];
+ }
+
+ return buf[0];
}
static inline int calc_divisor(int bps)
