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[PATCH for-4.5] watchdog/rc32434_wdt: fix ioctl error handling

From "Michael S. Tsirkin" <mst@redhat.com>
Newsgroups linux.kernel
Subject [PATCH for-4.5] watchdog/rc32434_wdt: fix ioctl error handling
Date 2016-02-28 16:50 +0100
Message-ID <r7bLz-4E3-9@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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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.

Cc: stable@vger.kernel.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

Untested.

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

diff --git a/drivers/watchdog/rc32434_wdt.c b/drivers/watchdog/rc32434_wdt.c
index 71e78ef..3a75f3b 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;
 	}
-- 
MST

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Thread

[PATCH for-4.5] watchdog/rc32434_wdt: fix ioctl error handling "Michael S. Tsirkin" <mst@redhat.com> - 2016-02-28 16:50 +0100
  Re: [PATCH for-4.5] watchdog/rc32434_wdt: fix ioctl error handling Guenter Roeck <linux@roeck-us.net> - 2016-02-28 17:00 +0100

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