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Date:   Fri, 18 Nov 2022 23:54:55 +0100
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Subject: Re: [PATCH] carl9170: Replace zero-length array of trailing structs
 with flex-array
Content-Language: de-DE
To:     Kees Cook <keescook@chromium.org>,
        Christian Lamparter <chunkeey@googlemail.com>
Cc:     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>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
References: <20221118211146.never.395-kees@kernel.org>
From:   Christian Lamparter <chunkeey@gmail.com>
In-Reply-To: <20221118211146.never.395-kees@kernel.org>
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On 11/18/22 22:11, 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@googlemail.com>
> Cc: Kalle Valo <kvalo@kernel.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Cc: linux-wireless@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Lamparter <chunkeey@gmail.com>

> ---
>   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 {