Re: [PATCH V2 3/6] mpcore_wdt: Fix WDIOC_SETOPTIONS handling

Sergei Shtylyov
2011-07-06T12:06:36Z

Hello.

On 05-07-2011 23:00, Vitaly Kuzmichev wrote:

> According to the include/linux/watchdog.h WDIOC_SETOPTIONS is
> classified as 'read from device' ioctl call:
> #define WDIOC_SETOPTIONS _IOR(WATCHDOG_IOCTL_BASE, 4, int)

> However, the driver 'mpcore_wdt' performs 'copy_from_user' only if
> _IOC_WRITE is set, thus the local variable 'uarg' which is used in
> WDIOC_SETOPTIONS handling remains uninitialized.

> The proper way to fix this is to bind WDIOC_SETOPTIONS to _IOW,
> but this will break compatibility.
> So adding additional condition for performing 'copy_from_user'.

> Signed-off-by: Vitaly Kuzmichev<vkuzmichev@mvista.com>
> ---
> drivers/watchdog/mpcore_wdt.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)

> diff --git a/drivers/watchdog/mpcore_wdt.c b/drivers/watchdog/mpcore_wdt.c
> index 7a3d6b2..b330a0a 100644
> --- a/drivers/watchdog/mpcore_wdt.c
> +++ b/drivers/watchdog/mpcore_wdt.c
> @@ -240,7 +240,8 @@ static long mpcore_wdt_ioctl(struct file *file, unsigned int cmd,
> if (_IOC_DIR(cmd)&& _IOC_SIZE(cmd)> sizeof(uarg))
> return -ENOTTY;
>
> - if (_IOC_DIR(cmd) & _IOC_WRITE) {
> + if (_IOC_DIR(cmd) & _IOC_WRITE

I think you need parens around this.

> + || cmd == WDIOC_SETOPTIONS) {
> ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
> if (ret)
> return -EFAULT;

WBR, Sergei