[PATCH 4.5 143/238] watchdog: rc32434_wdt: fix ioctl error handling

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.5 143/238] watchdog: rc32434_wdt: fix ioctl error handling
Date	2016-04-10 22:40 +0200
Message-ID	<rmuji-2ia-59@gated-at.bofh.it> (permalink)
References	<rmsr7-Nr-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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4.5-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Michael S. Tsirkin <mst@redhat.com>

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>

---
 drivers/watchdog/rc32434_wdt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/watchdog/rc32434_wdt.c
+++ b/drivers/watchdog/rc32434_wdt.c
@@ -237,7 +237,7 @@ static long rc32434_wdt_ioctl(struct fil
 			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;
 	}

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[PATCH 4.5 143/238] watchdog: rc32434_wdt: fix ioctl error handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 22:40 +0200

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