Re: [PATCH] carl9170: Replace zero-length array of trailing structs with flex-array

[Gustavo A. R. Silva]

On Fri, Nov 18, 2022 at 01:11:47PM -0800, Kees Cook wrote:
> Zero-length arrays are deprecated[1] and are being replaced with
> flexible array members in support of the ongoing efforts to tighten the
> FORTIFY_SOURCE routines on memcpy(), correctly instrument array indexing
> with UBSAN_BOUNDS, and to globally enable -fstrict-flex-arrays=3.
> 
> Replace zero-length array with flexible-array member.
> 
> This results in no differences in binary output.
> 
> [1] https://github.com/KSPP/linux/issues/78
> 
> Cc: Christian Lamparter <chunkeey@xxxxxxxxxxxxxx>
> Cc: Kalle Valo <kvalo@xxxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> Cc: "Gustavo A. R. Silva" <gustavoars@xxxxxxxxxx>
> Cc: linux-wireless@xxxxxxxxxxxxxxx
> Cc: netdev@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Another sneaky one. :p

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

Thanks!
--
Gustavo

> ---
>  drivers/net/wireless/ath/carl9170/fwcmd.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/carl9170/fwcmd.h b/drivers/net/wireless/ath/carl9170/fwcmd.h
> index 4a500095555c..ff4b3b50250c 100644
> --- a/drivers/net/wireless/ath/carl9170/fwcmd.h
> +++ b/drivers/net/wireless/ath/carl9170/fwcmd.h
> @@ -118,10 +118,10 @@ struct carl9170_reg_list {
>  } __packed;
>  
>  struct carl9170_write_reg {
> -	struct {
> +	DECLARE_FLEX_ARRAY(struct {
>  		__le32		addr;
>  		__le32		val;
> -	} regs[0] __packed;
> +	} __packed, regs);
>  } __packed;
>  
>  struct carl9170_write_reg_byte {
> -- 
> 2.34.1
>