From 36356a669eddb32917fc4b5c2b9b8bf80ede69de Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 12 Jan 2017 14:56:16 +0100 Subject: [PATCH] USB: serial: mct_u232: fix modem-status error handling 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 --- 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 885655315de1..edbc81f205c2 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]; -- 2.20.1