Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [RFC PATCH 06/40] soundwire: intel: prevent possible dereference
 in hw_params
To:     Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc:     alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
        tiwai@suse.de, broonie@kernel.org, vkoul@kernel.org,
        gregkh@linuxfoundation.org, jank@cadence.com,
        srinivas.kandagatla@linaro.org, slawomir.blauciak@intel.com,
        Sanyog Kale <sanyog.r.kale@intel.com>
References: <20190725234032.21152-1-pierre-louis.bossart@linux.intel.com>
 <20190725234032.21152-7-pierre-louis.bossart@linux.intel.com>
From:   Cezary Rojewski <cezary.rojewski@intel.com>
Message-ID: <1e814ab9-9606-88a5-3181-6cdb203671c3@intel.com>
Date:   Fri, 26 Jul 2019 11:45:04 +0200
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101
 Thunderbird/60.8.0
MIME-Version: 1.0
In-Reply-To: <20190725234032.21152-7-pierre-louis.bossart@linux.intel.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2019-07-26 01:39, Pierre-Louis Bossart wrote:
> This should not happen in production systems but we should test for
> all callback arguments before invoking the config_stream callback.
> 
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> ---
>   drivers/soundwire/intel.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
> index 68832e613b1e..497879dd9c0d 100644
> --- a/drivers/soundwire/intel.c
> +++ b/drivers/soundwire/intel.c
> @@ -509,7 +509,7 @@ static int intel_config_stream(struct sdw_intel *sdw,
>   			       struct snd_soc_dai *dai,
>   			       struct snd_pcm_hw_params *hw_params, int link_id)
>   {
> -	if (sdw->res->ops && sdw->res->ops->config_stream)
> +	if (sdw->res->ops && sdw->res->ops->config_stream && sdw->res->arg)
>   		return sdw->res->ops->config_stream(sdw->res->arg,
>   				substream, dai, hw_params, link_id);
>   
> 

Hmm, declaring local for sdw->res should prove useful here after 
addition of 4th sdw->res dereference.