Re: [PATCH] drm/exynos/ipp: Validate buffer enqueue requests

[Inki Dae <inki.dae@samsung.com>]

On 2015년 03월 04일 23:02, Marek Szyprowski wrote:
> From: Beata Michalska <b.michalska@samsung.com>
> 
> As for now there is no validation of incoming buffer
> enqueue request as far as the gem buffers are being
> concerned. This might lead to some undesired cases
> when the driver tries to operate on invalid buffers
> (wiht no valid gem object handle i.e.).
> Add some basic checks to rule out those potential issues.

Applied.

Thanks,
Inki Dae

> 
> Signed-off-by: Beata Michalska <b.michalska@samsung.com>
> [mszyprow: rebased onto v4.0-rc1 and adapted to recent ipp changes]
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  drivers/gpu/drm/exynos/exynos_drm_ipp.c | 44 +++++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_ipp.c b/drivers/gpu/drm/exynos/exynos_drm_ipp.c
> index 12ae9c4..ac35625 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_ipp.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_ipp.c
> @@ -476,6 +476,45 @@ err_clear:
>  	return ret;
>  }
>  
> +static int ipp_validate_mem_node(struct drm_device *drm_dev,
> +				 struct drm_exynos_ipp_mem_node *m_node,
> +				 struct drm_exynos_ipp_cmd_node *c_node)
> +{
> +	struct drm_exynos_ipp_config *ipp_cfg;
> +	unsigned int num_plane;
> +	unsigned long min_size, size;
> +	unsigned int bpp;
> +	int i;
> +
> +	/* The property id should already be varified */
> +	ipp_cfg = &c_node->property.config[m_node->prop_id];
> +	num_plane = drm_format_num_planes(ipp_cfg->fmt);
> +
> +	/**
> +	 * This is a rather simplified validation of a memory node.
> +	 * It basically verifies provided gem object handles
> +	 * and the buffer sizes with respect to current configuration.
> +	 * This is not the best that can be done
> +	 * but it seems more than enough
> +	 */
> +	for (i = 0; i < num_plane; ++i) {
> +		if (!m_node->buf_info.handles[i]) {
> +			DRM_ERROR("invalid handle for plane %d\n", i);
> +			return -EINVAL;
> +		}
> +		bpp = drm_format_plane_cpp(ipp_cfg->fmt, i);
> +		min_size = (ipp_cfg->sz.hsize * ipp_cfg->sz.vsize * bpp) >> 3;
> +		size = exynos_drm_gem_get_size(drm_dev,
> +					       m_node->buf_info.handles[i],
> +					       c_node->filp);
> +		if (min_size > size) {
> +			DRM_ERROR("invalid size for plane %d\n", i);
> +			return -EINVAL;
> +		}
> +	}
> +	return 0;
> +}
> +
>  static int ipp_put_mem_node(struct drm_device *drm_dev,
>  		struct drm_exynos_ipp_cmd_node *c_node,
>  		struct drm_exynos_ipp_mem_node *m_node)
> @@ -552,6 +591,11 @@ static struct drm_exynos_ipp_mem_node
>  	}
>  
>  	mutex_lock(&c_node->mem_lock);
> +	if (ipp_validate_mem_node(drm_dev, m_node, c_node)) {
> +		ipp_put_mem_node(drm_dev, c_node, m_node);
> +		mutex_unlock(&c_node->mem_lock);
> +		return ERR_PTR(-EFAULT);
> +	}
>  	list_add_tail(&m_node->list, &c_node->mem_list[qbuf->ops_id]);
>  	mutex_unlock(&c_node->mem_lock);
>  
> 

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