Re: [PATCH] thermal: Fix potential NULL pointer accesses

[Zhang Rui <rui.zhang@intel.com>]

On 二, 2012-08-07 at 22:36 -0700, Guenter Roeck wrote:
> The type parameter in thermal_zone_device_register and
> thermal_cooling_device_register can be NULL, indicating that no sysfs attribute
> for the type should be created. Only call strlen() and strcpy() on type if it is
> not NULL.
> 
> This patch addresses Coverity #102180 and #102182: Dereference before null check
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Acked-by: Zhang Rui <rui.zhang@intel.com>

> ---
> Applies on top of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux.git (thermal).
> 
>  drivers/thermal/thermal_sys.c |    8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index 5be8728..e69f76d 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -900,7 +900,7 @@ thermal_cooling_device_register(char *type, void *devdata,
>  	struct thermal_zone_device *pos;
>  	int result;
>  
> -	if (strlen(type) >= THERMAL_NAME_LENGTH)
> +	if (type && strlen(type) >= THERMAL_NAME_LENGTH)
>  		return ERR_PTR(-EINVAL);
>  
>  	if (!ops || !ops->get_max_state || !ops->get_cur_state ||
> @@ -917,7 +917,7 @@ thermal_cooling_device_register(char *type, void *devdata,
>  		return ERR_PTR(result);
>  	}
>  
> -	strcpy(cdev->type, type);
> +	strcpy(cdev->type, type ? : "");
>  	mutex_init(&cdev->lock);
>  	INIT_LIST_HEAD(&cdev->thermal_instances);
>  	cdev->ops = ops;
> @@ -1343,7 +1343,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
>  	int count;
>  	int passive = 0;
>  
> -	if (strlen(type) >= THERMAL_NAME_LENGTH)
> +	if (type && strlen(type) >= THERMAL_NAME_LENGTH)
>  		return ERR_PTR(-EINVAL);
>  
>  	if (trips > THERMAL_MAX_TRIPS || trips < 0 || mask >> trips)
> @@ -1365,7 +1365,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
>  		return ERR_PTR(result);
>  	}
>  
> -	strcpy(tz->type, type);
> +	strcpy(tz->type, type ? : "");
>  	tz->ops = ops;
>  	tz->device.class = &thermal_class;
>  	tz->devdata = devdata;