USB: serial: mct_u232: fix modem-status error handling

commit 36356a669eddb32917fc4b5c2b9b8bf80ede69de upstream.

Make sure to detect short control-message transfers so that errors are
logged when reading the modem status at open.

Note that while this also avoids initialising the modem status using
uninitialised heap data, these bits could not leak to user space as they
are currently not used.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2017-01-12 14:56:16 +01:00 committed by Greg Kroah-Hartman
parent ea04bd7914
commit 574c8b2aa0

View File

@ -322,8 +322,12 @@ static int mct_u232_get_modem_stat(struct usb_serial_port *port,
MCT_U232_GET_REQUEST_TYPE,
0, 0, buf, MCT_U232_GET_MODEM_STAT_SIZE,
WDR_TIMEOUT);
if (rc < 0) {
if (rc < MCT_U232_GET_MODEM_STAT_SIZE) {
dev_err(&port->dev, "Get MODEM STATus failed (error = %d)\n", rc);
if (rc >= 0)
rc = -EIO;
*msr = 0;
} else {
*msr = buf[0];