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Message-ID: <1ab422def27d43e1866b470a3f9d24aa@realtek.com>
Date: Fri, 21 Oct 2022 00:12:29 +0000
From: Ping-Ke Shih <pkshih@...ltek.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: "stable@...r.kernel.org" <stable@...r.kernel.org>,
Kevin Yang <kevin_yang@...ltek.com>,
Kalle Valo <kvalo@...nel.org>, Sasha Levin <sashal@...nel.org>
Subject: RE: [PATCH 6.0 681/862] wifi: rtw88: phy: fix warning of possible buffer overflow
> -----Original Message-----
> From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Sent: Wednesday, October 19, 2022 4:33 PM
> To: linux-kernel@...r.kernel.org
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>; stable@...r.kernel.org; Kevin Yang
> <kevin_yang@...ltek.com>; Ping-Ke Shih <pkshih@...ltek.com>; Kalle Valo <kvalo@...nel.org>; Sasha Levin
> <sashal@...nel.org>
> Subject: [PATCH 6.0 681/862] wifi: rtw88: phy: fix warning of possible buffer overflow
>
> From: Zong-Zhe Yang <kevin_yang@...ltek.com>
>
> [ Upstream commit 86331c7e0cd819bf0c1d0dcf895e0c90b0aa9a6f ]
>
> reported by smatch
>
> phy.c:854 rtw_phy_linear_2_db() error: buffer overflow 'db_invert_table[i]'
> 8 <= 8 (assuming for loop doesn't break)
>
> However, it seems to be a false alarm because we prevent it originally via
> if (linear >= db_invert_table[11][7])
> return 96; /* maximum 96 dB */
>
> Still, we adjust the code to be more readable and avoid smatch warning.
Like Pavel mentioned [1], this patch is to avoid smatch warning, not a really
bug. So, shouldn't take this patch.
[1] https://lore.kernel.org/linux-wireless/20221018093921.GD1264@duo.ucw.cz/
>
> Signed-off-by: Zong-Zhe Yang <kevin_yang@...ltek.com>
> Signed-off-by: Ping-Ke Shih <pkshih@...ltek.com>
> Signed-off-by: Kalle Valo <kvalo@...nel.org>
> Link: https://lore.kernel.org/r/20220727065003.28340-5-pkshih@realtek.com
> Signed-off-by: Sasha Levin <sashal@...nel.org>
> ---
> drivers/net/wireless/realtek/rtw88/phy.c | 21 ++++++++-------------
> 1 file changed, 8 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/wireless/realtek/rtw88/phy.c b/drivers/net/wireless/realtek/rtw88/phy.c
> index 8982e0c98dac..da1efec0aa85 100644
> --- a/drivers/net/wireless/realtek/rtw88/phy.c
> +++ b/drivers/net/wireless/realtek/rtw88/phy.c
> @@ -816,23 +816,18 @@ static u8 rtw_phy_linear_2_db(u64 linear)
> u8 j;
> u32 dB;
>
> - if (linear >= db_invert_table[11][7])
> - return 96; /* maximum 96 dB */
> -
> for (i = 0; i < 12; i++) {
> - if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][7])
> - break;
> - else if (i > 2 && linear <= db_invert_table[i][7])
> - break;
> + for (j = 0; j < 8; j++) {
> + if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][j])
> + goto cnt;
> + else if (i > 2 && linear <= db_invert_table[i][j])
> + goto cnt;
> + }
> }
>
> - for (j = 0; j < 8; j++) {
> - if (i <= 2 && (linear << FRAC_BITS) <= db_invert_table[i][j])
> - break;
> - else if (i > 2 && linear <= db_invert_table[i][j])
> - break;
> - }
> + return 96; /* maximum 96 dB */
>
> +cnt:
> if (j == 0 && i == 0)
> goto end;
>
> --
> 2.35.1
>
>
>
>
> ------Please consider the environment before printing this e-mail.
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