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Subject: Re: [lvc-project] [PATCH] iio: chemical: scd30: Add check for NULL in
 scd30_i2c_command
To:     Anastasia Belova <abelova@astralinux.ru>,
        Tomasz Duszynski <tomasz.duszynski@octakon.com>
Cc:     Lars-Peter Clausen <lars@metafoo.de>, lvc-project@linuxtesting.org,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Jonathan Cameron <jic23@kernel.org>
References: <20230113133320.7531-1-abelova@astralinux.ru>
From:   Alexey Khoroshilov <khoroshilov@ispras.ru>
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Message-ID: <c0c7d2d7-648d-feb3-14ea-c2ab3baddfb1@ispras.ru>
Date:   Fri, 13 Jan 2023 21:41:40 +0300
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On 13.01.2023 16:33, Anastasia Belova wrote:
> Check rsp for NULL-pointer before dereferencing.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: e510190e0139 ("iio: chemical: scd30: add I2C interface driver")
> Signed-off-by: Anastasia Belova <abelova@astralinux.ru>
> ---
>  drivers/iio/chemical/scd30_i2c.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/chemical/scd30_i2c.c b/drivers/iio/chemical/scd30_i2c.c
> index bae479a4721f..84baf67fc0ce 100644
> --- a/drivers/iio/chemical/scd30_i2c.c
> +++ b/drivers/iio/chemical/scd30_i2c.c
> @@ -101,8 +101,10 @@ static int scd30_i2c_command(struct scd30_state *state, enum scd30_cmd cmd, u16
>  			return -EIO;
>  		}
>  
> -		*rsp++ = buf[i];
> -		*rsp++ = buf[i + 1];
> +		if (rsp) {
> +			*rsp++ = buf[i];
> +			*rsp++ = buf[i + 1];
> +		}
>  	}
>  
>  	return 0;
> 


It seems it is better to put the whole validation loop under if (rsp)
check.

--
Alexey