RE: [PATCH][next] rtlwifi: Replace fake flex-array with flex-array member

[Ping-Ke Shih <pkshih@realtek.com>]

> -----Original Message-----
> From: Gustavo A. R. Silva <gustavoars@kernel.org>
> Sent: Friday, March 24, 2023 9:12 AM
> To: Ping-Ke Shih <pkshih@realtek.com>; Kalle Valo <kvalo@kernel.org>; David S. Miller <davem@davemloft.net>;
> Eric Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>
> Cc: linux-wireless@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Gustavo A. R.
> Silva <gustavoars@kernel.org>; linux-hardening@vger.kernel.org
> Subject: [PATCH][next] rtlwifi: Replace fake flex-array with flex-array member
> 
> Zero-length arrays as fake flexible arrays are deprecated and we are
> moving towards adopting C99 flexible-array members instead.
> 
> Address the following warning found with GCC-13 and
> -fstrict-flex-arrays=3 enabled:
> In function ‘fortify_memset_chk’,
>     inlined from ‘rtl_usb_probe’ at drivers/net/wireless/realtek/rtlwifi/usb.c:1044:2:
> ./include/linux/fortify-string.h:430:25: warning: call to ‘__write_overflow_field’ declared with
> attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()?
> [-Wattribute-warning]
>   430 |                         __write_overflow_field(p_size_field, size);
>       |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
> 
> Link: https://github.com/KSPP/linux/issues/21
> Link: https://github.com/KSPP/linux/issues/277
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Acked-by: Ping-Ke Shih <pkshih@realtek.com>

> ---
>  drivers/net/wireless/realtek/rtlwifi/wifi.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtlwifi/wifi.h b/drivers/net/wireless/realtek/rtlwifi/wifi.h
> index 31f9e9e5c680..082af216760f 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/wifi.h
> +++ b/drivers/net/wireless/realtek/rtlwifi/wifi.h
> @@ -2831,7 +2831,7 @@ struct rtl_priv {
>          * beyond  this structure like:
>          * rtl_pci_priv or rtl_usb_priv
>          */
> -       u8 priv[0] __aligned(sizeof(void *));
> +       u8 priv[] __aligned(sizeof(void *));
>  };
> 
>  #define rtl_priv(hw)           (((struct rtl_priv *)(hw)->priv))
> --
> 2.34.1
> 
> 
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