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Date:   Wed, 16 Jun 2021 21:58:09 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Kees Cook <keescook@chromium.org>
Cc:     netdev@vger.kernel.org, Lennert Buytenhek <buytenh@wantstofly.org>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Romain Perier <romain.perier@gmail.com>,
        Allen Pais <allen.lkml@gmail.com>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        wengjianfeng <wengjianfeng@yulong.com>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Lv Yunlong <lyl2019@mail.ustc.edu.cn>,
        linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: Re: [PATCH] mwl8k: Avoid memcpy() over-reading of ETH_SS_STATS
Message-ID: <YMpX0S/Xeis0kKoP@lunn.ch>
References: <20210616195242.1231287-1-keescook@chromium.org>
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On Wed, Jun 16, 2021 at 12:52:42PM -0700, Kees Cook wrote:
> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field bounds checking for memcpy(), memmove(), and memset(), avoid
> intentionally reading across neighboring array fields. Use the
> sub-structure address directly.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  drivers/net/wireless/marvell/mwl8k.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/marvell/mwl8k.c b/drivers/net/wireless/marvell/mwl8k.c
> index 84b32a5f01ee..3bf6571f4149 100644
> --- a/drivers/net/wireless/marvell/mwl8k.c
> +++ b/drivers/net/wireless/marvell/mwl8k.c
> @@ -4552,7 +4552,7 @@ static int mwl8k_cmd_update_stadb_add(struct ieee80211_hw *hw,
>  	else
>  		rates = sta->supp_rates[NL80211_BAND_5GHZ] << 5;
>  	legacy_rate_mask_to_array(p->legacy_rates, rates);
> -	memcpy(p->ht_rates, sta->ht_cap.mcs.rx_mask, 16);
> +	memcpy(p->ht_rates, &sta->ht_cap.mcs, 16);
>  	p->interop = 1;
>  	p->amsdu_enabled = 0;
>  
> @@ -5034,7 +5034,7 @@ mwl8k_bss_info_changed_sta(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
>  			ap_legacy_rates =
>  				ap->supp_rates[NL80211_BAND_5GHZ] << 5;
>  		}
> -		memcpy(ap_mcs_rates, ap->ht_cap.mcs.rx_mask, 16);
> +		memcpy(ap_mcs_rates, &ap->ht_cap.mcs, 16);
>  
>  		rcu_read_unlock();

This does not appear to have anything to do with ETH_SS_STATS which is
what the Subject: says.

     Andrew