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From:   Jes Sorensen <jes.sorensen@gmail.com>
Message-ID: <bd6d437e-6dfc-bb7f-d74e-84714e952a8e@gmail.com>
Date:   Fri, 19 Aug 2022 09:43:53 -0400
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Subject: Re: [PATCH] wifi: rtl8xxxu: tighten bounds checking in
 rtl8xxxu_read_efuse()
Content-Language: en-US
To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     Kalle Valo <kvalo@kernel.org>, linux-wireless@vger.kernel.org,
        kernel-janitors@vger.kernel.org
References: <Yv8eGLdBslLAk3Ct@kili>
In-Reply-To: <Yv8eGLdBslLAk3Ct@kili>
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On 8/19/22 01:22, Dan Carpenter wrote:
> There some bounds checking to ensure that "map_addr" is not out of
> bounds before the start of the loop.  But the checking needs to be
> done as we iterate through the loop because "map_addr" gets larger as
> we iterate.
> 
> Fixes: 26f1fad29ad9 ("New driver: rtl8xxxu (mac80211)")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  .../net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c  | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)

Looks reasonable to me.

Acked-by: Jes Sorensen <Jes.Sorensen@gmail.com>


> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> index c66f0726b253..f3a107f19cf5 100644
> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> @@ -1878,13 +1878,6 @@ static int rtl8xxxu_read_efuse(struct rtl8xxxu_priv *priv)
>  
>  		/* We have 8 bits to indicate validity */
>  		map_addr = offset * 8;
> -		if (map_addr >= EFUSE_MAP_LEN) {
> -			dev_warn(dev, "%s: Illegal map_addr (%04x), "
> -				 "efuse corrupt!\n",
> -				 __func__, map_addr);
> -			ret = -EINVAL;
> -			goto exit;
> -		}
>  		for (i = 0; i < EFUSE_MAX_WORD_UNIT; i++) {
>  			/* Check word enable condition in the section */
>  			if (word_mask & BIT(i)) {
> @@ -1895,6 +1888,13 @@ static int rtl8xxxu_read_efuse(struct rtl8xxxu_priv *priv)
>  			ret = rtl8xxxu_read_efuse8(priv, efuse_addr++, &val8);
>  			if (ret)
>  				goto exit;
> +			if (map_addr >= EFUSE_MAP_LEN - 1) {
> +				dev_warn(dev, "%s: Illegal map_addr (%04x), "
> +					 "efuse corrupt!\n",
> +					 __func__, map_addr);
> +				ret = -EINVAL;
> +				goto exit;
> +			}
>  			priv->efuse_wifi.raw[map_addr++] = val8;
>  
>  			ret = rtl8xxxu_read_efuse8(priv, efuse_addr++, &val8);