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 checking 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 ivpu_job.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Cc: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Cc: Oded Gabbay <ogabbay@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Tom Rix <trix@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Cc: llvm@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/accel/ivpu/ivpu_job.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/accel/ivpu/ivpu_job.h b/drivers/accel/ivpu/ivpu_job.h
index aa1f0b9479b0..5514c2d8a609 100644
--- a/drivers/accel/ivpu/ivpu_job.h
+++ b/drivers/accel/ivpu/ivpu_job.h
@@ -51,7 +51,7 @@ struct ivpu_job {
 	u32 job_id;
 	u32 engine_idx;
 	size_t bo_count;
-	struct ivpu_bo *bos[];
+	struct ivpu_bo *bos[] __counted_by(bo_count);
 };
 
 int ivpu_submit_ioctl(struct drm_device *dev, void *data, struct drm_file *file);
-- 
2.34.1

On Fri, Sep 22, 2023 at 10:54:17AM -0700, 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 checking 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 ivpu_job.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
> Cc: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
> Cc: Oded Gabbay <ogabbay@kernel.org>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: Nick Desaulniers <ndesaulniers@google.com>
> Cc: Tom Rix <trix@redhat.com>
> Cc: dri-devel@lists.freedesktop.org
> Cc: llvm@lists.linux.dev
> Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>

Please apply the patch via whatever tree is appropriate. Or if I have
to take it via drm-misc, please let me know.

Regards
Stanislaw

> ---
>  drivers/accel/ivpu/ivpu_job.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/accel/ivpu/ivpu_job.h b/drivers/accel/ivpu/ivpu_job.h
> index aa1f0b9479b0..5514c2d8a609 100644
> --- a/drivers/accel/ivpu/ivpu_job.h
> +++ b/drivers/accel/ivpu/ivpu_job.h
> @@ -51,7 +51,7 @@ struct ivpu_job {
>  	u32 job_id;
>  	u32 engine_idx;
>  	size_t bo_count;
> -	struct ivpu_bo *bos[];
> +	struct ivpu_bo *bos[] __counted_by(bo_count);
>  };
>  
>  int ivpu_submit_ioctl(struct drm_device *dev, void *data, struct drm_file *file);
> -- 
> 2.34.1
>

On Fri, 22 Sep 2023 10:54:17 -0700, 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 checking 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 ivpu_job.
> 
> [...]

Thanks Stanislaw! I'll take it through my for-next/hardening tree then:

[1/1] accel/ivpu: Annotate struct ivpu_job with __counted_by
      https://git.kernel.org/kees/c/2eabbbb8275b

Take care,

-- 
Kees Cook