Re: [PATCH] uinput strnlen bugfix

[Aristeu Rozanski]

On Sun, Feb 06, 2011 at 11:40:17PM -0800, Dmitry Torokhov wrote:
> Hmm, not particularly fond with the construct, how about below instead?
> 
> Btw, having "Signed-off-by: " from David would be nice.
> 
> Thanks.
> 
> -- 
> Dmitry
> 
> Input: uinput - fix setting up device name
> 
> From: David Herrmann <dh.herrmann@xxxxxxxxxxxxxx>
> 
> The check for non-empty device name was botched since we tried to account
> for extra space for the terminating zero at the same time. Convert to
> kstrndup() to avoid this problem.
> 
> Acked-by: Aristeu Rozanski <aris@xxxxxxxxx>
> Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
> ---
> 
>  drivers/input/misc/uinput.c |   13 ++++++-------
>  1 files changed, 6 insertions(+), 7 deletions(-)
> 
> 
> diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
> index 82542a1..c0888e3 100644
> --- a/drivers/input/misc/uinput.c
> +++ b/drivers/input/misc/uinput.c
> @@ -347,8 +347,7 @@ static int uinput_setup_device(struct uinput_device *udev, const char __user *bu
>  {
>  	struct uinput_user_dev	*user_dev;
>  	struct input_dev	*dev;
> -	char			*name;
> -	int			i, size;
> +	int			i;
>  	int			retval;
>  
>  	if (count != sizeof(struct uinput_user_dev))
> @@ -373,19 +372,19 @@ static int uinput_setup_device(struct uinput_device *udev, const char __user *bu
>  
>  	udev->ff_effects_max = user_dev->ff_effects_max;
>  
> -	size = strnlen(user_dev->name, UINPUT_MAX_NAME_SIZE) + 1;
> -	if (!size) {
> +	/* Ensure name is filled in */
> +	if (!user_dev->name[0]) {
>  		retval = -EINVAL;
>  		goto exit;
>  	}
>  
>  	kfree(dev->name);
> -	dev->name = name = kmalloc(size, GFP_KERNEL);
> -	if (!name) {
> +	dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
> +			     GFP_KERNEL);
> +	if (!dev->name) {
>  		retval = -ENOMEM;
>  		goto exit;
>  	}
> -	strlcpy(name, user_dev->name, size);
>  
>  	dev->id.bustype	= user_dev->id.bustype;
>  	dev->id.vendor	= user_dev->id.vendor;
even better
ACK

-- 
Aristeu

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