drm/i915: Catch dirt in unused execbuffer fields

We need to make sure that userspace keeps on following the contract,
otherwise we won't be able to use the reserved fields at all.

v2: Add DRM_DEBUG (Chris)

Testcase: igt/gem_exec_params/*-dirt
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index c7ef65c3ae91c8a656d812ce7b4a543606409147..b9dcc2869edc89a512ee39fe8afe0977266e2001 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1123,6 +1123,11 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
                        ret = -EFAULT;
                        goto pre_mutex_err;
                }
+       } else {
+               if (args->DR1 || args->DR4 || args->cliprects_ptr) {
+                       DRM_DEBUG("0 cliprects but dirt in cliprects fields\n");
+                       return -EINVAL;
+               }
        }
 
        intel_runtime_pm_get(dev_priv);
@@ -1400,6 +1405,11 @@ i915_gem_execbuffer2(struct drm_device *dev, void *data,
                return -EINVAL;
        }
 
+       if (args->rsvd2 != 0) {
+               DRM_DEBUG("dirty rvsd2 field\n");
+               return -EINVAL;
+       }
+
        exec2_list = kmalloc(sizeof(*exec2_list)*args->buffer_count,
                             GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
        if (exec2_list == NULL)