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

[Luben Tuikov]

On 2023-10-03 19:29, Kees Cook wrote:
> 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@xxxxxxx>
> Cc: "Christian König" <christian.koenig@xxxxxxx>
> Cc: "Pan, Xinhui" <Xinhui.Pan@xxxxxxx>
> Cc: David Airlie <airlied@xxxxxxxxx>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> Cc: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx>
> Cc: Luben Tuikov <luben.tuikov@xxxxxxx>
> Cc: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> Cc: Felix Kuehling <Felix.Kuehling@xxxxxxx>
> Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Cc: linux-hardening@xxxxxxxxxxxxxxx
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Reviewed-by: Luben Tuikov <luben.tuikov@xxxxxxx>
-- 
Regards,
Luben

> ---
>  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,