Re: [PATCH 2/2][next] wifi: brcmfmac: Use struct_size() in code ralated to struct brcmf_dload_data_le

From: Kees Cook <keescook@chromium.org>
To: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Hante Meuleman <hante.meuleman@broadcom.com>,
	Franky Lin <franky.lin@broadcom.com>,
	Arend van Spriel <aspriel@gmail.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>,
	SHA-cyfmac-dev-list@infineon.com,
	brcm80211-dev-list.pdl@broadcom.com, netdev@vger.kernel.org,
	linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-hardening@vger.kernel.org
Subject: Re: [PATCH 2/2][next] wifi: brcmfmac: Use struct_size() in code ralated to struct brcmf_dload_data_le
Date: Wed, 16 Nov 2022 14:23:52 -0800	[thread overview]
Message-ID: <202211161423.2531CADA73@keescook> (raw)
In-Reply-To: <41845ad3660ed4375f0c03fd36a67b2e12fafed5.1668548907.git.gustavoars@kernel.org>

On Tue, Nov 15, 2022 at 03:55:34PM -0600, Gustavo A. R. Silva wrote:
> Prefer struct_size() over open-coded versions of idiom:
> 
> sizeof(struct-with-flex-array) + sizeof(typeof-flex-array-elements) * count
> 
> where count is the max number of items the flexible array is supposed to
> contain.
> 
> In this particular case, in the open-coded version sizeof(typeof-flex-array-elements)
> is implicit in _count_ because the type of the flex array data is u8:
> 
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/fwil_types.h:941:
>  941 struct brcmf_dload_data_le {
>  942         __le16 flag;
>  943         __le16 dload_type;
>  944         __le32 len;
>  945         __le32 crc;
>  946         u8 data[];
>  947 };
> 
> Link: https://github.com/KSPP/linux/issues/160
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook