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Subject: Re: [PATCH 04/23] ASoC: cros_ec_codec: remove null pointer
 dereference warning
To:     Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        alsa-devel@alsa-project.org
Cc:     tiwai@suse.de, broonie@kernel.org, linux-kernel@vger.kernel.org,
        Cheng-Yi Chiang <cychiang@chromium.org>,
        Guenter Roeck <groeck@chromium.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Benson Leung <bleung@chromium.org>
References: <20210312182246.5153-1-pierre-louis.bossart@linux.intel.com>
 <20210312182246.5153-5-pierre-louis.bossart@linux.intel.com>
From:   Enric Balletbo i Serra <enric.balletbo@collabora.com>
Message-ID: <dd3fd255-4397-80d6-2114-3b37b5be5c08@collabora.com>
Date:   Mon, 15 Mar 2021 11:39:27 +0100
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Hi Pierre-Louis,

Thank you for you patch.

On 12/3/21 19:22, Pierre-Louis Bossart wrote:
> Cppcheck complains of a possible issue:
> 
> sound/soc/codecs/cros_ec_codec.c:98:10: warning: Possible null pointer
> dereference: in [nullPointer]
>   memcpy(in, msg->data, insize);
>          ^
> sound/soc/codecs/cros_ec_codec.c:162:34: note: Calling function
> 'send_ec_host_command', 5th argument 'NULL' value is 0
>        (uint8_t *)&p, sizeof(p), NULL, 0);
>                                  ^
> sound/soc/codecs/cros_ec_codec.c:98:10: note: Null pointer dereference
>   memcpy(in, msg->data, insize);
>          ^
> 
> In practice the access to the pointer is protected by another
> argument, but this is likely to fool other static analysis tools. Add
> a test to avoid doing the memcpy if the pointer is NULL or the size is
> zero.
> 
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

Looks good to me, so

Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>


> ---
>  sound/soc/codecs/cros_ec_codec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/cros_ec_codec.c b/sound/soc/codecs/cros_ec_codec.c
> index c4772f82485a..a201d652aca2 100644
> --- a/sound/soc/codecs/cros_ec_codec.c
> +++ b/sound/soc/codecs/cros_ec_codec.c
> @@ -94,7 +94,7 @@ static int send_ec_host_command(struct cros_ec_device *ec_dev, uint32_t cmd,
>  	if (ret < 0)
>  		goto error;
>  
> -	if (insize)
> +	if (in && insize)
>  		memcpy(in, msg->data, insize);
>  
>  	ret = 0;
>