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Message-ID: <39b42c868d1aa01bb421733aac32f072dc85e393.camel@perches.com>
Subject: Re: [PATCH 3/3] rtlwifi: rtl8192de: fix array size limit in for-loop
From:   Joe Perches <joe@perches.com>
To:     Colin King <colin.king@canonical.com>,
        Ping-Ke Shih <pkshih@realtek.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Tue, 03 Aug 2021 11:11:21 -0700
In-Reply-To: <20210803144949.79433-3-colin.king@canonical.com>
References: <20210803144949.79433-1-colin.king@canonical.com>
         <20210803144949.79433-3-colin.king@canonical.com>
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On Tue, 2021-08-03 at 15:49 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the size of the entire array is being used in a for-loop
> for the element count. While this works since the elements are u8
> sized, it is preferred to use ARRAY_SIZE to get the element count
> of the array.
[]
> diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c b/drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c
[]
> @@ -1366,7 +1366,7 @@ u8 rtl92d_get_rightchnlplace_for_iqk(u8 chnl)
> ?	u8 place = chnl;
> 
> ?	if (chnl > 14) {
> -		for (place = 14; place < sizeof(channel_all); place++) {
> +		for (place = 14; place < ARRAY_SIZE(channel_all); place++) {
> ?			if (channel_all[place] == chnl)
> ?				return place - 13;
> ?		}

Thanks.

It seems a relatively common copy/paste use in rtlwifi

$ git grep -P -n 'for\b.*<\s*sizeof\s*\(\s*\w+\w*\)\s*;' drivers/net/wireless/realtek/rtlwifi/
drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c:893:               for (place = 14; place < sizeof(channel5g); place++) {
drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c:1368:              for (place = 14; place < sizeof(channel_all); place++) {
drivers/net/wireless/realtek/rtlwifi/rtl8192de/phy.c:2430:      for (i = 0; i < sizeof(channel5g); i++)
drivers/net/wireless/realtek/rtlwifi/rtl8192ee/phy.c:2781:              for (place = 14; place < sizeof(channel_all); place++) {
drivers/net/wireless/realtek/rtlwifi/rtl8723be/phy.c:2170:              for (place = 14; place < sizeof(channel_all); place++) {
drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c:3610:              for (place = 14; place < sizeof(channel_all); place++)