[Intel-gfx] [PATCH 3/6] drm: Verify gamma/degamma LUT size

[Sharma, Shashank]

Regards

Shashank


On 2/24/2018 12:55 AM, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> While we want to potentially support multiple different gamma/degamma
> LUT sizes we can (and should) at least check that the blob length
> is a multiple of the LUT entry size.
I dint understand the exact idea behind doing this, how is this going to 
benefit ? May be a bit more description ?
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>   drivers/gpu/drm/drm_atomic.c | 15 +++++++++++----
>   1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 8945357212ba..933edec0299d 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -413,6 +413,7 @@ drm_atomic_replace_property_blob_from_id(struct drm_device *dev,
>   					 struct drm_property_blob **blob,
>   					 uint64_t blob_id,
>   					 ssize_t expected_size,
> +					 ssize_t expected_size_mod,
>   					 bool *replaced)
>   {
>   	struct drm_property_blob *new_blob = NULL;
> @@ -422,7 +423,13 @@ drm_atomic_replace_property_blob_from_id(struct drm_device *dev,
>   		if (new_blob == NULL)
>   			return -EINVAL;
>   
> -		if (expected_size > 0 && expected_size != new_blob->length) {
> +		if (expected_size > 0 &&
> +		    new_blob->length != expected_size) {
> +			drm_property_blob_put(new_blob);
> +			return -EINVAL;
> +		}
One line needed here, matching the previous if() pattern
> +		if (expected_size_mod > 0 &&
> +		    new_blob->length % expected_size_mod != 0) {
>   			drm_property_blob_put(new_blob);
>   			return -EINVAL;
>   		}
> @@ -470,7 +477,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
>   		ret = drm_atomic_replace_property_blob_from_id(dev,
>   					&state->degamma_lut,
>   					val,
> -					-1,
> +					-1, sizeof(struct drm_color_lut),
>   					&replaced);
>   		state->color_mgmt_changed |= replaced;
>   		return ret;
> @@ -478,7 +485,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
>   		ret = drm_atomic_replace_property_blob_from_id(dev,
>   					&state->ctm,
>   					val,
> -					sizeof(struct drm_color_ctm),
> +					sizeof(struct drm_color_ctm), -1,
>   					&replaced);
>   		state->color_mgmt_changed |= replaced;
>   		return ret;
> @@ -486,7 +493,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
>   		ret = drm_atomic_replace_property_blob_from_id(dev,
>   					&state->gamma_lut,
>   					val,
> -					-1,
> +					-1, sizeof(struct drm_color_lut),
>   					&replaced);
>   		state->color_mgmt_changed |= replaced;
>   		return ret;