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

From: Zhang Rui
Date: Wed Aug 08 2012 - 20:43:39 EST


On ä, 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@xxxxxxxxxxxx>

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

> ---
> 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;


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