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

Michael S. Tsirkin
2016-02-28T15:44:16Z

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