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: v3.11.10~31
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5e13a42e913a83bbff33cf919d575778e8e76df7;p=thirdparty%2Fkernel%2Fstable.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 3bac4693c0382..23dc9d1dc99eb 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -1580,7 +1580,11 @@ 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)