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

From	Guenter Roeck <linux@roeck-us.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH for-4.5] watchdog/rc32434_wdt: fix ioctl error handling
Date	2016-02-28 17:00 +0100
Message-ID	<r7bVg-4Ib-7@gated-at.bofh.it> (permalink)
References	<r7bLz-4E3-9@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 02/28/2016 07:44 AM, Michael S. Tsirkin wrote:
> 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>

Acked-by: Guenter Roeck <linux@roeck-us.net>

> ---
>
> 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;
>   	}
>

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[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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