From 00f244650faff0528541ca1e5927a4c7b024bfa4 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 12 Jan 2017 14:56:16 +0100 Subject: USB: serial: mct_u232: fix modem-status error handling [ Upstream commit 36356a669eddb32917fc4b5c2b9b8bf80ede69de ] 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 Signed-off-by: Johan Hovold Signed-off-by: Sasha Levin --- drivers/usb/serial/mct_u232.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c index 1c9ff791a6fe..a6c07c6be25f 100644 --- a/drivers/usb/serial/mct_u232.c +++ b/drivers/usb/serial/mct_u232.c @@ -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]; -- cgit v1.2.3