From: Michael S. Tsirkin <mst@redhat.com>
Date: Sun, 28 Feb 2016 15:44:09 +0000 (+0200)
Subject: watchdog: rc32434_wdt: fix ioctl error handling
X-Git-Tag: firefly_0821_release~176^2~4^2~50^2~81
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=6a4cdbf56201f983f8177e3845fcb47d25d4fcb0;p=firefly-linux-kernel-4.4.55.git

watchdog: rc32434_wdt: fix ioctl error handling

commit 10e7ac22cdd4d211cef99afcb9371b70cb175be6 upstream.

Calling return copy_to_user(...) in an ioctl will not do the right thing
if there's a pagefault: copy_to_user returns the number of bytes not
copied in this case.

Fix up watchdog/rc32434_wdt to do
	return copy_to_user(...)) ?  -EFAULT : 0;

instead.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/watchdog/rc32434_wdt.c b/drivers/watchdog/rc32434_wdt.c
index 71e78ef4b736..3a75f3b53452 100644
--- a/drivers/watchdog/rc32434_wdt.c
+++ b/drivers/watchdog/rc32434_wdt.c
@@ -237,7 +237,7 @@ static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
 			return -EINVAL;
 		/* Fall through */
 	case WDIOC_GETTIMEOUT:
-		return copy_to_user(argp, &timeout, sizeof(int));
+		return copy_to_user(argp, &timeout, sizeof(int)) ? -EFAULT : 0;
 	default:
 		return -ENOTTY;
 	}