[PATCH 10/19] drm: only allow render node ioctls through control node

[Ilija Hadzic <ihadzic@research.bell-labs.com>]

The render-node manipulation ioctls are supposed to be
issued through control node only. Add a check and return
-EPERM to user space if access is attempted through a
node other than a control node.

Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com>
---
 drivers/gpu/drm/drm_stub.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index d7ec39c..6629dd7 100644
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -552,6 +552,10 @@ int drm_render_node_create_ioctl(struct drm_device *dev, void *data,
 	int total_ids, i;
 	uint32_t __user *ids_ptr;
 
+	/* allow access through control node only */
+	if (file_priv->minor != dev->control)
+		return -EPERM;
+
 	/* trivial case: render node with no display resources */
 	if (args->num_crtc == 0 && args->num_encoder == 0 &&
 	    args->num_connector == 0 && args->num_plane == 0) {
@@ -603,6 +607,10 @@ int drm_render_node_remove_ioctl(struct drm_device *dev, void *data,
 	struct drm_render_node_remove *args = data;
 	int ret;
 
+	/* allow access through control node only */
+	if (file_priv->minor != dev->control)
+		return -EPERM;
+
 	ret = drm_destroy_render_node(dev, args->node_minor_id);
 	return ret;
 }
-- 
1.7.8.5