[PATCH 07/16] drm: only allow render node ioctls through control node

[Ilija Hadzic]

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 at 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 12260f0..fb241e6 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 &&
@@ -602,6 +606,10 @@ 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