Re: [PATCH] drm/amdgpu: Annotate struct amdgpu_bo_list with __counted_by

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 04.10.23 um 01:29 schrieb Kees Cook:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
>
> As found with Coccinelle[1], add __counted_by for struct amdgpu_bo_list.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: "Christian König" <christian.koenig@amd.com>
> Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Cc: Luben Tuikov <luben.tuikov@amd.com>
> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> Cc: Felix Kuehling <Felix.Kuehling@amd.com>
> Cc: amd-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-hardening@vger.kernel.org
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c | 2 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> index 6f5b641b631e..781e5c5ce04d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.c
> @@ -84,6 +84,7 @@ int amdgpu_bo_list_create(struct amdgpu_device *adev, struct drm_file *filp,
>   
>   	kref_init(&list->refcount);
>   
> +	list->num_entries = num_entries;
>   	array = list->entries;
>   
>   	for (i = 0; i < num_entries; ++i) {
> @@ -129,7 +130,6 @@ int amdgpu_bo_list_create(struct amdgpu_device *adev, struct drm_file *filp,
>   	}
>   
>   	list->first_userptr = first_userptr;
> -	list->num_entries = num_entries;
>   	sort(array, last_entry, sizeof(struct amdgpu_bo_list_entry),
>   	     amdgpu_bo_list_entry_cmp, NULL);
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
> index 6a703be45d04..555cd6d877c3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bo_list.h
> @@ -56,7 +56,7 @@ struct amdgpu_bo_list {
>   	 */
>   	struct mutex bo_list_mutex;
>   
> -	struct amdgpu_bo_list_entry entries[];
> +	struct amdgpu_bo_list_entry entries[] __counted_by(num_entries);
>   };
>   
>   int amdgpu_bo_list_get(struct amdgpu_fpriv *fpriv, int id,