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    Subject[PATCH 6.0 681/862] wifi: rtw88: phy: fix warning of possible buffer overflow
    Date
    From: Zong-Zhe Yang <kevin_yang@realtek.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.

    Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
    Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
    Signed-off-by: Kalle Valo <kvalo@kernel.org>
    Link: https://lore.kernel.org/r/20220727065003.28340-5-pkshih@realtek.com
    Signed-off-by: Sasha Levin <sashal@kernel.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


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