From: Johan Hovold <jhovold@gmail.com>
Date: Wed, 9 Oct 2013 15:01:09 +0000 (+0200)
Subject: USB: mos7840: fix tiocmget error handling
X-Git-Tag: firefly_0821_release~6453^2~308
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=7471b5f424c444727014ec6a72b6008e62fafef4;p=firefly-linux-kernel-4.4.55.git

USB: mos7840: fix tiocmget error handling

commit a91ccd26e75235d86248d018fe3779732bcafd8d upstream.

Make sure to return errors from tiocmget rather than rely on
uninitialised stack data.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 2c1749da1f7e..8b3d0abe7e14 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -1593,7 +1593,11 @@ static int mos7840_tiocmget(struct tty_struct *tty)
 		return -ENODEV;
 
 	status = mos7840_get_uart_reg(port, MODEM_STATUS_REGISTER, &msr);
+	if (status != 1)
+		return -EIO;
 	status = mos7840_get_uart_reg(port, MODEM_CONTROL_REGISTER, &mcr);
+	if (status != 1)
+		return -EIO;
 	result = ((mcr & MCR_DTR) ? TIOCM_DTR : 0)
 	    | ((mcr & MCR_RTS) ? TIOCM_RTS : 0)
 	    | ((mcr & MCR_LOOPBACK) ? TIOCM_LOOP : 0)