Re: [PATCH 5/7] drm/omap: gem: dumb: pitch is an output

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Nov 05, 2014 at 02:25:17PM +0100, Thierry Reding wrote:
> From: Thierry Reding <treding@nvidia.com>
> 
> When creating a dumb buffer object using the DRM_IOCTL_MODE_CREATE_DUMB
> IOCTL, only the width, height, bpp and flags fields are inputs. The
> caller is not guaranteed to zero out or set handle, pitch and size.
> Drivers must not treat these values as possible inputs, otherwise they
> may use uninitialized memory during the computation of the framebuffer
> size.
> 
> The OMAP driver uses the pitch field passed in by userspace as a minimum
> and only override it if the driver-computed pitch is larger than what
> userspace provided. To prevent this from causing overallocation, fix the
> minimum pitch to 0 to enforce the driver-computed pitch.
> 
> Signed-off-by: Thierry Reding <treding@nvidia.com>

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  drivers/gpu/drm/omapdrm/omap_gem.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c b/drivers/gpu/drm/omapdrm/omap_gem.c
> index e4849413ee80..bff60b73995b 100644
> --- a/drivers/gpu/drm/omapdrm/omap_gem.c
> +++ b/drivers/gpu/drm/omapdrm/omap_gem.c
> @@ -613,7 +613,7 @@ int omap_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
>  	union omap_gem_size gsize;
>  
>  	/* in case someone tries to feed us a completely bogus stride: */
> -	args->pitch = align_pitch(args->pitch, args->width, args->bpp);
> +	args->pitch = align_pitch(0, args->width, args->bpp);
>  	args->size = PAGE_ALIGN(args->pitch * args->height);
>  
>  	gsize = (union omap_gem_size){
> -- 
> 2.1.3
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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