dmaengine: Annotate with __counted_by

[PATCH 11/21] dmaengine: st_fdma: Annotate struct st_fdma_desc with __counted_by

Posted by Kees Cook 2 years, 5 months ago

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 st_fdma_desc.

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

Cc: Vinod Koul <vkoul@kernel.org>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: dmaengine@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/dma/st_fdma.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/st_fdma.h b/drivers/dma/st_fdma.h
index fa15b97a3bab..f296412e96b6 100644
--- a/drivers/dma/st_fdma.h
+++ b/drivers/dma/st_fdma.h
@@ -97,7 +97,7 @@ struct st_fdma_desc {
 	struct st_fdma_chan *fchan;
 	bool iscyclic;
 	unsigned int n_nodes;
-	struct st_fdma_sw_node node[];
+	struct st_fdma_sw_node node[] __counted_by(n_nodes);
 };
 
 enum st_fdma_type {
-- 
2.34.1

Re: [PATCH 11/21] dmaengine: st_fdma: Annotate struct st_fdma_desc with __counted_by

Posted by Gustavo A. R. Silva 2 years, 5 months ago


On 8/17/23 17:58, 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 st_fdma_desc.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Vinod Koul <vkoul@kernel.org>
> Cc: Patrice Chotard <patrice.chotard@foss.st.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: dmaengine@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
>   drivers/dma/st_fdma.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/st_fdma.h b/drivers/dma/st_fdma.h
> index fa15b97a3bab..f296412e96b6 100644
> --- a/drivers/dma/st_fdma.h
> +++ b/drivers/dma/st_fdma.h
> @@ -97,7 +97,7 @@ struct st_fdma_desc {
>   	struct st_fdma_chan *fchan;
>   	bool iscyclic;
>   	unsigned int n_nodes;
> -	struct st_fdma_sw_node node[];
> +	struct st_fdma_sw_node node[] __counted_by(n_nodes);
>   };
>   
>   enum st_fdma_type {