[Intel-gfx] [PATCH 1/2] drm/i915: Check that the relocation points to within the target

[Chris Wilson]

Eric noted a potential concern with the low bits not being strictly used
as part of the absolute offset (instead part of the command stream to the
GPU), but in practice that should not be an issue.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Tested-by: Andy Whitcroft <apw at canonical.com>
Cc: Eric Anholt <eric at anholt.net>
CC: stable at kernel.org
---
 drivers/gpu/drm/i915/i915_gem.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e0da986..11242c6 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3004,6 +3004,16 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
 			return -EINVAL;
 		}
 
+		if (reloc->delta >= target_obj->size) {
+			DRM_ERROR("Relocation beyond target object bounds: "
+				  "obj %p target %d delta %d size %d.\n",
+				  obj, reloc->target_handle,
+				  (int) reloc->delta, (int) target_obj->size);
+			drm_gem_object_unreference(target_obj);
+			i915_gem_object_unpin(obj);
+			return -EINVAL;
+		}
+
 		if (reloc->write_domain & I915_GEM_DOMAIN_CPU ||
 		    reloc->read_domains & I915_GEM_DOMAIN_CPU) {
 			DRM_ERROR("reloc with read/write CPU domains: "
-- 
1.6.3.3