[PATCH 2/5] drm/vmwgfx: check master authentication in surface_ref ioctls

[Thomas Hellstrom]

On 11/1/19 2:05 PM, Emil Velikov wrote:
> From: Emil Velikov <emil.velikov at collabora.com>
>
> With later commit we'll rework DRM authentication handling. Namely
> DRM_AUTH will not be a requirement for DRM_RENDER_ALLOW ioctls.
>
> Since vmwgfx does isolation for primary clients in different master
> realms, the DRM_AUTH can be dropped.
>
> The only place where authentication matters, is surface_reference ioctls
> whenever a legacy (non-prime) handle is used. For those ioctls we call
> vmw_surface_handle_reference(), where we explicitly check if the client
> is both a) master and b) unauthenticated - bailing out as result.
>
> Otherwise the usual isolation path kicks in and we're all good.
>
> v2: Reword commit message, since the isolation work has landed.
>
> Cc: VMware Graphics <linux-graphics-maintainer at vmware.com>
> Cc: Thomas Hellstrom <thellstrom at vmware.com>
> Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
> ---
>  drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> index 1f989f3605c8..596e5c1bc2c1 100644
> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
> @@ -936,6 +936,13 @@ vmw_surface_handle_reference(struct vmw_private *dev_priv,
>  		user_srf = container_of(base, struct vmw_user_surface,
>  					prime.base);
>  
> +		/* Error out if we are unauthenticated master */

Shouldn't this be "Error out if we are unauthenticated primary" ?

Otherwise

Reviewed-by: Thomas Hellstrom <thellstrom at vmware.com>


> +		if (drm_is_primary_client(file_priv) &&
> +		    !file_priv->authenticated) {
> +			ret = -EACCES;
> +			goto out_bad_resource;
> +		}
> +
>  		/*
>  		 * Make sure the surface creator has the same
>  		 * authenticating master, or is already registered with us.