[PATCH 1/1] booke/wdt: fix incorrect WDIOC_GETSUPPORT return path

[Tabi Timur-B04825]

On Mon, Jul 30, 2012 at 3:15 AM, Tiejun Chen <tiejun.chen at windriver.com> wrote:
> We miss that correct WDIOC_GETSUPPORT return path when perform
> copy_to_user() properly.

Thanks for catching this.  I'm amazed that this driver still has bugs like this.

> diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c
> index 3fe82d0..2be7f29 100644
> --- a/drivers/watchdog/booke_wdt.c
> +++ b/drivers/watchdog/booke_wdt.c
> @@ -162,12 +162,13 @@ static long booke_wdt_ioctl(struct file *file,
>                                 unsigned int cmd, unsigned long arg)
>  {
>         u32 tmp = 0;
> -       u32 __user *p = (u32 __user *)arg;
> +       void __user *argp = (u32 __user *)arg;
> +       u32 __user *p = argp;

You don't need to create 'argp'.  The existing 'p' variable will work
in the copy_to_user() call.

> +               return copy_to_user(argp, &ident,
> +                               sizeof(ident)) ? -EFAULT : 0;

This can fit in one line, especially if you use 'p' instead of 'argp'.

-- 
Timur Tabi
Linux kernel developer at Freescale