[patch v2] drm/amdgpu: missing bounds check in amdgpu_set_pp_force_state()

[Christian König]

Am 16.06.2016 um 10:30 schrieb Dan Carpenter:
> There is no limit on high "idx" can go.  It should be less than
> ARRAY_SIZE(data.states) which is 16.
>
> The "data" variable wasn't declared in that scope so I shifted the code
> around a bit to make it work.  Also I made "idx" unsigned.
>
> Fixes: f3898ea12fc1 ('drm/amd/powerplay: add some sysfs interfaces for powerplay.')
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>

Acked-by: Christian König <christian.koenig at amd.com>.

> ---
> v2: make idx unsigned
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> index 589b36e..0e13d80 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> @@ -270,30 +270,28 @@ static ssize_t amdgpu_set_pp_force_state(struct device *dev,
>   	struct drm_device *ddev = dev_get_drvdata(dev);
>   	struct amdgpu_device *adev = ddev->dev_private;
>   	enum amd_pm_state_type state = 0;
> -	long idx;
> +	unsigned long idx;
>   	int ret;
>   
>   	if (strlen(buf) == 1)
>   		adev->pp_force_state_enabled = false;
> -	else {
> -		ret = kstrtol(buf, 0, &idx);
> +	else if (adev->pp_enabled) {
> +		struct pp_states_info data;
>   
> -		if (ret) {
> +		ret = kstrtoul(buf, 0, &idx);
> +		if (ret || idx >= ARRAY_SIZE(data.states)) {
>   			count = -EINVAL;
>   			goto fail;
>   		}
>   
> -		if (adev->pp_enabled) {
> -			struct pp_states_info data;
> -			amdgpu_dpm_get_pp_num_states(adev, &data);
> -			state = data.states[idx];
> -			/* only set user selected power states */
> -			if (state != POWER_STATE_TYPE_INTERNAL_BOOT &&
> -				state != POWER_STATE_TYPE_DEFAULT) {
> -				amdgpu_dpm_dispatch_task(adev,
> -						AMD_PP_EVENT_ENABLE_USER_STATE, &state, NULL);
> -				adev->pp_force_state_enabled = true;
> -			}
> +		amdgpu_dpm_get_pp_num_states(adev, &data);
> +		state = data.states[idx];
> +		/* only set user selected power states */
> +		if (state != POWER_STATE_TYPE_INTERNAL_BOOT &&
> +		    state != POWER_STATE_TYPE_DEFAULT) {
> +			amdgpu_dpm_dispatch_task(adev,
> +					AMD_PP_EVENT_ENABLE_USER_STATE, &state, NULL);
> +			adev->pp_force_state_enabled = true;
>   		}
>   	}
>   fail: