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 fw_node.

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

Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: linux1394-devel@lists.sourceforge.net
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/firewire/core.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index 2a05f411328f..95c10f3d2282 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -191,7 +191,7 @@ struct fw_node {
 	/* Upper layer specific data. */
 	void *data;
 
-	struct fw_node *ports[];
+	struct fw_node *ports[] __counted_by(port_count);
 };
 
 static inline struct fw_node *fw_node_get(struct fw_node *node)
-- 
2.34.1

Hi,

On Fri, Sep 22, 2023 at 10:53:35AM -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 fw_node.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>
> Cc: linux1394-devel@lists.sourceforge.net
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  drivers/firewire/core.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied to for-next branch, thanks.


Regards

Takashi Sakamoto

On 9/22/23 11:53, 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 fw_node.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Takashi Sakamoto <o-takashi@sakamocchi.jp>
> Cc: linux1394-devel@lists.sourceforge.net
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
-- 
Gustavo

> ---
>   drivers/firewire/core.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
> index 2a05f411328f..95c10f3d2282 100644
> --- a/drivers/firewire/core.h
> +++ b/drivers/firewire/core.h
> @@ -191,7 +191,7 @@ struct fw_node {
>   	/* Upper layer specific data. */
>   	void *data;
>   
> -	struct fw_node *ports[];
> +	struct fw_node *ports[] __counted_by(port_count);
>   };
>   
>   static inline struct fw_node *fw_node_get(struct fw_node *node)