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 5c6dade6cf529e68f1f0b86a4845db891122705b..96d0aae6f975aec234493869ee4f1f637c9a3e8c 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)