Linux Virtualization - Dec 2016 - [PATCH] drm/ttm: use designated initializers

Prepare to mark sensitive kernel structures for randomization by making
sure they're using designated initializers. These were identified during
allyesconfig builds of x86, arm, and arm64, with most initializer fixes
extracted from grsecurity.

Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/gpu/drm/virtio/virtgpu_ttm.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ttm.c
b/drivers/gpu/drm/virtio/virtgpu_ttm.c
index 4a1de9f81193..63b3d5d35cf6 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ttm.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ttm.c
@@ -198,11 +198,11 @@ static void ttm_bo_man_debug(struct ttm_mem_type_manager
*man,
 }
 
 static const struct ttm_mem_type_manager_func virtio_gpu_bo_manager_func = {
-	ttm_bo_man_init,
-	ttm_bo_man_takedown,
-	ttm_bo_man_get_node,
-	ttm_bo_man_put_node,
-	ttm_bo_man_debug
+	.init = ttm_bo_man_init,
+	.takedown = ttm_bo_man_takedown,
+	.get_node = ttm_bo_man_get_node,
+	.put_node = ttm_bo_man_put_node,
+	.debug = ttm_bo_man_debug
 };
 
 static int virtio_gpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
-- 
2.7.4


-- 
Kees Cook
Nexus Security

On Sun, Dec 18, 2016 at 10:53 PM, Alexander Stein
<alexander.stein at systec-electronic.com> wrote:
> Hello Kees,
>
> While understanding what your patches (I've seen the other ones as
well) do
> themself, I still don't get what your intention is, e.g. why you need
this?
> Apart from a better readability.
>
> On Friday 16 December 2016 16:59:29, Kees Cook wrote:
>> Prepare to mark sensitive kernel structures for randomization by making
>> sure they're using designated initializers.
>
> Can you please elaborate what you mean with that sentence?
Hi! Sure: the coming (and optional) gcc plugin "randstruct" performs
structure layout randomization, which means that static initializers
cannot be "ordered" (they must be "designated"), since the
place were
layout randomization occurs happens separate from how static
initializers are applied.

This change from ordered to designated is just to help the compiler do
the right thing.

-Kees

-- 
Kees Cook
Nexus Security